ASUS P8Z68V PRO Motherboard Review

Manufacturer: ASUSTeK Computer Inc.
Product Name: Intel Z68-Express motherboard
Model Number: P8Z68-V Pro
Price As Tested:$209.00 at Newegg.com

Full Disclosure: The product sample used in this article was provided by ASUSTeK Computer Inc.

Intel's Sandy Bridge CPUs and their accompanying Cougar Point chipsets brought a new level of price/performance to the enthusiast market. There was just one problem: you had to choose between a motherboard with the H67 chipset, which enabled the on-CPU graphics and Intel's new Quick Sync transcoding engine, or a motherboard based on the P67 chipset, which enabled the amazing overclocking ability of the "K"-series CPUs. You could have one, or the other, but not both...until now. Intel's new Z68 chipset gives the enthusiast both capabilities in a single platform, and ASUS throws in their own enhancements to create one of the most impressive motherboards Benchmark Reviews has ever seen.

It's been barely four months since Intel announced the original "x67" chipsets and Sandy Bridge CPUs. The new CPU architecture, combined with a 32nm process, produced processors with amazing performance per clock at low power drains. The Core i7 2600K processor outperforms even the Core i7 980X in tasks that can't make full use of the latter's 12 possible threads, and it does so at 1/3 the cost, while producing much less heat. Enthusiasts rushed to embrace this new architecture despite its limitations, but were broadsided by Intel's admission of a bug in the Cougar Point chipsets that could render some of the SATA ports inoperable over time. Intel and its channel partners were forced to recall and replace millions of motherboards, and the debacle is estimated to have cost the chip giant about a billion dollars. (If you're in the market for a P67/H67 motherboard, make sure you get the fixed "B3" version.)

How will new P67 owners feel now that their shiny new (replaced) motherboards have arguably been obsoleted? I hasten to add that both Intel and ASUS insist that the P67 is still very much alive and a supported product, and say that there's room in the market for both chipsets. Of course this will depend to some degree on the pricing of Z68 motherboards, and to another on the tolerance users have for cutting-edge technology that might not work quite as smoothly as it should.

ASUS outfits their new Z68 motherboard with the same technologies they've developed over the years for their other motherboard products, including:

• EFI - User Extensible Firmware Interface (BIOS replacement) with Graphical User Interface f
• ASUS BT GO! - Adds an onboard Bluetooth 2.1 receiver with BT Turbo remote and BT-to-Net functionality
• DIGI+ VRM - Precision digital Voltage Regulator Module replaces analog management
• AI Charger - Boost the current output of your USB ports to charge iPads and other high-drain devices, or to charge regular devices faster
• AI Suite II - Combines DIGI+ VRM, EPU, TurboV EVO, BT GO!, FAN Xpert, and Probe II software into one program
• ASUS DIP2 - Dual Intelligent Processors integrated onto the motherboard:
  • ASUS TPU (TurboV Processing Unit) Relieves parts of process-intensive tasks from CPU
  • ASUS EPU (Energy Processing Unit) Reduces power drain by up to 80%
• MemOK! - Enables the motherboard to boot up successfully even if there might be some memory compatibility issues.

But the real news about the Z68 is its switchable graphics. In a surprise move, Intel has licensed Lucid's "Virtu" technology to allow a Z68 motherboard to support on-the-fly switching between a Sandy Bridge processor's integrated video and a discrete graphics card, which promises to reduce power consumption by only using the separate graphics card when it's needed. (The P8Z68-V Pro motherboard also supports a desktop variant of NVIDIA's "Optimus" video-switching technology called "Synergy", but this wasn't ready at the time of this review.)

The Intel Z68 Express Chipset

Although the Z68 chipset had been rumored for some weeks, it's still a little surprising how rapidly it appeared after the introduction of the P67 chipset. This architecture diagram summarizes its features:

If you're looking at this diagram and thinking "This looks just like the P67 Express block diagram", then you're right! There are only two differences:

1. The "Intel Smart Response Technology", an intelligent caching scheme that uses a small (20-64G) SSD as a cache to a selected hard drive. I examine Smart Response Technology in this article.
2. The "Intel FDI" (Flexible Display Interface) link between the processor and the chipset, culminating in the "Digital Display" section.

Everything else is the same; disappointingly, Intel has not given us any increase in the number of PCI-E 2.0 lanes, which remain at 16 from the processor plus 8 from the chipset for a total of 24. Compared to the 40 lanes available on an X58-based system or the 42 lanes available on an AMD 890FX system, the Z68 still comes up short. Users running multiple graphics cards are limited to 8 PCI-E lanes per card with two cards, or 8x4x4 with three cards. While tests have shown that there's very little degradation in performance with 8x8 dual-card systems as opposed to 16x16 systems, enthusiasts tend to look askance at limitations like this, even though they might be of little real-world significance.

But there can be some less obvious effects: remember that PCI-E lanes are also used to support SuperSpeed USB 3.0 and SATA 6Gbp/s ports, and the Z68 has four of each. In fact ASUS' own reviewer's guide for this board suggests disconnecting any unnecessary USB devices before running performance tests in order to get the best results.

Intel Smart Response Technology is an intelligent caching scheme that uses a small SSD (20G to 64G) to cache your system's hard drive.

Aside from the paucity of PCI-E lanes, though, it's all good. The Z68's most significant new feature is its support for integrated Sandy Bridge graphics even when one or more separate graphics cards are installed. This has several advantages: on its own, it means you can run two monitors directly from the motherboard, or four or six with one or two separate graphics cards. With Lucid Virtu technology, you have power savings when the performance of the separate cards isn't needed, and the ability to make use of Intel's Quick Sync video transcoding feature even if you have a video card installed. Benchmark Reviews examines Virtu technology in detail in a separate article.

Closer Look: ASUS P8Z68

The box for the P8Z68 lacks the Velcro-secured flap and transparent motherboard viewing window of ASUS' "Extreme" motherboards, but does try to highlight the features of the board. Although a "Virtu" logo is on the front of the box (obscured by the motherboard in this image), what Virtu is isn't explained anywhere. Since this is one of the most important features of the board, I think it should be called out in more detail.

The accessories bundled are two sets of SATA cables (one with locking connectors), an SLI bridge, a rear-panel connector for the native USB 3.0 header on the board, an I/O shield, and a manual. This pre-production review board didn't come with a CD, although the production versions obviously will.

The ASUS P8Z68-V Pro board's appearance and layout are almost identical to the P8P67 EVO board, but that's not a bad thing. Good component layout, attractive colors, and interesting blue-anodized aluminum heat sinks give the board some visual flair. One interesting feature I haven't seen before is dual CPU fan headers, each PWM enabled, which will be handy for handling dual-fan heatsinks without having to resort to a Y-cable. While the board lacks Extreme-level features like voltage measuring points, it does offer on-board power and reset switches, as well as switches to enable or disable the TPU and EPU functions, as well as ASUS' ubiquitous "MemOK!" button.

The slot layout of the P8Z68 is identical to that of the P8P67 EVO: three PCI-E x16 slots, two PCI-E x1 slots, and two "plain" PCI slots. The spacing of the first two PCI-E x16 slots allows some breathing room between two double-slot graphics cards. A double-slot card in the last slot will occlude the on-board power and reset switches as well as most of the USB ports.

The rear ports, from the left, are four USB 2.0; the integrated BlueTooth module, two more USB 2.0 ports, and an ESATA port; an optical audio out and HDMI port; VGA and DVI outputs; gigabit Ethernet and two USB 3.0 ports, and last the analog audio panel. The FireWire (IEEE 1394) port of the P8P67 and P8P67 Evo has vanished, but few will miss it, and there are two FireWire headers on the board should your case support FireWire. ASUS has done away with legacy PS/2 keyboard and mouse ports on its newer boards, and I for one don't miss them.

I'll continue looking at this board in the next section.

Closer Look Continued

The area around the processor socket is very open, with low-profile heat sinks on the power circuitry leaving plenty of room for large CPU coolers. Fortunately Intel's Socket 1156 layout uses the same cooler mounting holes as Socket 1155. Although it's not apparent in this image, the four DIMM sockets use ASUS' single-retaining-latch design, which I don't like since it's all too easy to overlook memory that's not fully seated in the slot.

Peering under the heat sinks, we can see the chokes in the power supply area around the processor socket. Like ASUS' P8P67 boards, the P8Z68 has 12-phase power for the processor, and adds another four phases for the integrated GPU. ASUS calls this "12+4" regulation. At low loads, fewer phases are used, thus saving power; while the "DIGI+ VRM" circuitry ramps up the number of phases in use as power demand increases.

The EPU, TPU, and MemOK! switches are clustered together at the lower right corner of the board. See the tiny surface-mount LED by the MemOK! switch labeled "DRAM_LED"? This is one of four "POST state LEDs" on the board, the others being CPU_LED, VGA_LED, and BOOT_DEVICE_LED. If a problem with any of these components occurs during the power-on self test sequence, the corresponding LED will stay lit. While not as informative as a full POST code display, it's still good enough for most situations.

Looking to the left, we see a native USB 3.0 header next to the 8 SATA ports. The four leftmost SATA ports are SATA 3G, while the rightmost four are SATA 6G, the two gray ports controlled by the Z68 chipset and the two dark blue ports by a separate Marvell controller. If your case doesn't have a native USB 3.0 connector, ASUS thoughtfully supplies a cable that brings these extra USB 3.0 ports out to a back panel connector.

This ASMedia 1042 USB 3.0 controller replaces the NEC D720200 USB 3.0 controller that's been the common choice for SuperSpeed USB support until now. The P8Z68 is stuffed with ASMedia chips, including the 1083 PCI-E to PCI bridge, the ASM1440 multiplexer/demultiplexer, and the 1442 HDMI support chip. Other third-party chips in this board include a Nuvotron NCT6776F for board temperature monitoring and fan control, a VIA VT6308P for IEEE 1394 (FireWire), and a Marvel 88SE9120 for the two extra SATA 6Gbp/s ports.

Along the side of the board are the SPDIF audio connector, power and reset buttons, three USB headers (blue), two FireWire headers (black), and the front panel connector.

ASUS' TurboV Processing Unit (TPU) custom processor, seen here next to the front panel header block, is what enables their very effective automatic overclocking features. Their custom EPU chip manages the board's power use but is hidden under a heat sink covering the power circuitry by the processor socket.

Now that we've examined the board, it's time to start the performance testing.

Motherboard Testing Methodology

Testing the P8Z68-V Pro motherboard required a lot more work than a typical motherboard, because in addition to the standard performance tests, I had to run multiple video performance tests using the various configurations possible. For the standard performance tests I compared the ASUS P8Z68-V Pro motherboard to an ASUS P8P67 motherboard. WIll the Z68 Express chipset bring any performance advantage over the P67 Express?

P67 Test System

• Motherboard: ASUS P8P67 (BIOS 0905)
• Processor: Intel Core i7 2600K
• System Memory: 2x2G G.SKILL DDR3 1333Mhz 9-9-9-24
• Disk Drive: Western Digital Raptor 300 WD30 00HLFS-01G6U1
• Operating System: Windows 7 x64 Home Premium with SP1
• Graphics adapter: AMD Radeon 6850

Z68 Test System

• Motherboard: ASUS P8Z68-V Pro (BIOS 8801)
• Processor: Intel Core i7 2600K
• System Memory: 2x2G G.SKILL DDR3 1333Mhz 9-9-9-24
• Disk Drive: Western Digital Raptor 300 WD30 00HLFS-01G6U1
• Operating System: Windows 7 x64 Home Premium with SP1
• Graphics adapter: Intel HD Graphics 3000 / AMD Radeon 6850
• CPU Cooler: Thermalright Silver Arrow

Benchmark Applications

• AIDA64 Extreme Edition v1.60
• CINEBENCH R11.5
• PassMark Performance Test v7.0
• Handbrake 0.95
• x264 HD Benchmarl 3.19
• Blender
• SPECviewPerf 11
• SPECapc LightWave
• Street Fighter IV Benchmark

Each benchmark application was run on the P67-based motherboard and on the P8Z68-V Pro. The P8Z68 was tested using its internal video (iGPU), Lucid Virtu in "i-Mode", and overclocked with a Radeon 6850 video card running in "native mode" (i.e. Virtu disabled). Virtu "i-Mode" should switch any rendering tasks to the Radeon 6850 as long as Virtu has been configured for the application in question. Since the integrated GPU of the Sandy Bridge processors uses the same L3 cache as does the processor cores, we might expect a small performance hit when the iGPU is in use.

AIDA64 Extreme Edition Results

AIDA64 Extreme Edition is the evolution of Lavalys' "Everest Ultimate Edition". Hungarian developer FinalWire acquired the rights to Everest in late November 2010, and renamed the product "AIDA64". The Everest product was discontinued and FinalWire is offering 1-year license keys to those with active Everest keys.

AIDA64 is a full 64-bit benchmark and test suite utilizing MMX, 3DNow! and SSE instruction set extensions, and will scale up to 32 processor cores. An enhanced 64-bit System Stability Test module is also available to stress the whole system to its limits. For legacy processors, all benchmarks and the System Stability Test are available in 32-bit versions as well. Additionally, AIDA64 adds new hardware to its database, including 300 solid-state drives. On top of the usual ATA auto-detect information the new SSD database enables AIDA64 to display flash memory type, controller model, physical dimensions, and data transfer performance data. AIDA64 v1.00 also implements SSD-specific SMART disk health information for Indilinx, Intel, JMicron, Samsung, and SandForce controllers.

All of the benchmarks used in this test- Queen, Photoworxx, ZLib, hash, and AES- rely on basic x86 instructions, and consume very little system memory while also being aware of Hyper-Threading, multi-processors, and multi-core processors. Of all the tests in this review, AIDA64 is the one that best isolates the processor's performance from the rest of the system. While this is useful in that it more directly compares processor performance, readers should remember that virtually no "real world" programs will mirror these results.

Since none of the AIDA64 tests are concerned with video, the results are pretty even until we reach the overclocked P8Z68. At 4.94GHz, we see a significant (40%) improvement in the Queen benchmark, a minor improvement in PhotoWorxx, and none to speak of in the AES benchmark. (Note that the AES results are scaled to make them fit the chart.)

Although the visual difference is small due to scaling, ZLIB picks up a 44% boost with the overclocked processor, while the Hash benchmark increases by 41%

CINEBENCH R11.5 Benchmarks

Maxon CINEBENCH is a real-world test suite that assesses a computer's performance capabilities. CINEBENCH is based on Maxon's award-winning animation software, Cinema 4D, which is used extensively by studios and production houses worldwide for 3D content creation. Maxon software has been used in blockbuster movies such as Spider-Man, Star Wars, The Chronicles of Narnia, and many more. CINEBENCH Release 11.5 includes the ability to more accurately test the industry's latest hardware, including systems with up to 64 processor threads, and the testing environment better reflects the expectations of today's production demands. A more streamlined interface makes testing systems and reading results incredibly straightforward.

The CINEBENCH R11.5 test scenario comprises three tests: an OpenGL-based test that models a simple car chase, and single-core and multi-core versions of a CPU-bound computation using all of a system's processing power to render a photo-realistic 3D scene, "No Keyframes", the viral animation by AixSponza. This scene makes use of various algorithms to stress all available processor cores, and all the rendering is performed by the CPU: the graphics card is not involved except as a display device. The multi-core version of the rendering benchmark uses as many cores as the processor has, including the "virtual cores" in processors that support Hyper-Threading. The resulting "CineMark" is a dimensionless number only useful for comparisons with results generated from the same version of CINEBENCH.

I mentioned earlier that Virtu mode couldn't be enabled for some applications. This is true for CINEBENCH, where the i-Mode results for the OpenGL test are actually slightly slower than those for simply using the Sandy Bridge GPU on its own. The reason is

Overclocking yields substantial benefits for the CPU tests, though, with the single CPU test picking up 31% and the multi-core test increasing by 41%.

PassMark Performance Test 7.0

The PassMark PerformanceTest allows you to objectively benchmark a PC using a variety of different speed tests and compare the results to other computers. PassMark comprises a complete suite of tests for your computer, including CPU tests, 2D and 3D graphics tests, disk tests, memory tests, and even tests to determine the speed of your system's optical drive. PassMark tests support Hyper-Threading and systems with multiple CPUs, and allow you to save benchmark results to disk (or to export them to HTML, text, GIF, and BMP formats).

Knowledgeable users can use the Advanced Testing section to alter the parameters for the disk, network, graphics, multitasking, and memory tests, and created individual, customized testing suites. PassMark computes a "CPU Marks" score based on the scores of the individual tests in each test suite. For this review I used the CPU, 2D Graphics, and 3D Graphics tests.

CPU Marks increase by 37% with overclocking. The 2D Mark results are interesting: note that the score for the Sandy Bridge 2600K's iGPU is actually higher than that of the native Radeon 6850 used on the P8P67 and P8Z68! In fact on the test platform, the iGPU's score of 669 is 39% better than the score when using the 6850! Intel HD Graphics 3000 (the marketing name for the 2600K's integrated GPU) may not be for gamers, but as long as images stay in 2D, it rocks.

3D Marks show the iGPU's weakness, though. Here Virtu's i-Mode was able to handle the switch, and its 2837 score is 490% better than the iGPU.

Handbrake Media Encoding

It's a truism that consumer-level computer performance reached the "fast enough" point years ago, where increases in system performance don't make thing any faster for most people. Web browsing, e-mail, word processing, and even most games won't benefit dramatically from a super-fast CPU. There are some exceptions, though, and media encoding is one of them: transcoding video, especially high-definition video, can bring the strongest system to its knees. Fortunately, media transcoding is one of those things that (depending on the design of the code, of course) that scales really well with both clock speed and the number of cores, so the more you have of both, the better your results will be.

The free and open-source Handbrake 0.95 video transcoder is an example of a program that makes full use of the computational resources available. For this test I used Handbrake 0.95 to transcode a standard-definition episode of Family Guy to the "iPhone & iPod Touch" presets, and recorded the total time (in seconds) it took to transcode the video.

Surprisingly, the P8Z68 turns in about 10% better scores than the P8P67, even at stock clock speeds. Overclocking helps a lot, dropping the transcoding time by 23%.

x264Bench HD 3.19

Tech ARP's x264 HD Benchmark comprises the Avisynth video scripting engine, an x264 encoder, a sample 720P video file, and a script file that actually runs the benchmark. The script invokes four two-pass encoding runs and reports the average frames per second encoded as a result. The script file is a simple batch file, so you could edit the encoding parameters if you were interested, although your results wouldn't then be comparable to others.

The ASUS P8Z68-V Pro turns in fractionally better scores than the P8P67 on runs 1 and 2, and identical scores on runs 3 and 4. Overclocking boosts the results by an average of 37%.

SPECviewperf 11 Tests

The Standard Performance Evaluation Corporation is "...a non-profit corporation formed to establish, maintain and endorse a standardized set of relevant benchmarks that can be applied to the newest generation of high-performance computers." Their free SPECviewperf benchmark incorporates code and tests contributed by several other companies and is designed to stress computers in a reproducible way. SPECviewperf 11 was released in June 2010 and incorporates an expanded range of capabilities and tests. Note that results from previous versions of SPECviewperf cannot be compared with results from the latest version, as even benchmarks with the same name have been updated with new code and models.

SPECviewperf comprises test code from several vendors of professional graphics modeling, rendering, and visualization software. Most of the tests emphasize the CPU over the graphics card, and have between 5 and 13 sub-sections. For this review I ran the Lightwave, Maya, and Seimens Teamcenter Visualization tests. Results are reported as abstract scores, with higher being better.

Lightwave

The lightwave-01 viewset was created from traces of the graphics workloads generated by the SPECapc for Lightwave 9.6 benchmark.

The models for this viewset range in size from 2.5 to 6 million vertices, with heavy use of vertex buffer objects (VBOs) mixed with immediate mode. GLSL shaders are used throughout the tests. Applications represented by the viewset include 3D character animation, architectural review, and industrial design.

Maya

The maya-03 viewset was created from traces of the graphics workload generated by the SPECapc for Maya 2009 benchmark. The models used in the tests range in size from 6 to 66 million vertices, and are tested with and without vertex and fragment shaders.

State changes such as those executed by the application- including matrix, material, light and line-stipple changes- are included throughout the rendering of the models. All state changes are derived from a trace of the running application.

Siemens Teamcenter Visualization Mockup

The tcvis-02 viewset is based on traces of the Siemens Teamcenter Visualization Mockup application (also known as VisMockup) used for visual simulation. Models range from 10 to 22 million vertices and incorporate vertex arrays and fixed-function lighting.

State changes such as those executed by the application- including matrix, material, light and line-stipple changes- are included throughout the rendering of the model. All state changes are derived from a trace of the running application.

The Lightwave test is apparently beyond the capability of the Sandy Bridge integrated GPU; the result page just noted "Fail". The iGPU was able to complete the Maya and TCVIS tests, but again this is one of the applications for which Virtu didn't work, explaining the low scores for i-Mode in the last two tests. This is a good example of a non-gaming use for the extra processing power of a discrete graphics card.

SPECapc Lightwave

SPECapc (Application Performance Characterization) tests are fundamentally different from the SPECviewperf tests. While SPECviewperf tests incorporate code from the various test programs directly into the benchmark, the SPECapc tests are separate scripts and datasets that are run against a stand-alone installation of the program being benchmarked. SPECapc group members sponsor applications and work with end-users, user groups, publications and ISVs to select and refine workloads, which consist of data sets and benchmark script files. Workloads are determined by end-users and ISVs, not SPECapc group members. These workloads will evolve over time in conjunction with end-users' needs and the increasing functionality of PCs and workstations.

For this test, I ran the SPECapc "Lightwave" benchmark against a trial installation of Newtek's Lightwave 3D product. The benchmark, developed in cooperation with NewTek, provides realistic workloads that simulate a typical LightWave 3D workflow. It contains 11 datasets ranging from 64,000 to 1.75 million polygons and representing such applications as 3D character animation, architectural review, and industrial design. Scores for individual workloads are composited under three categories: interactive, render and multitask.

The benchmark puts special emphasis on processes that benefit from multi-threaded computing, such as animation, OpenGL playback, deformations, and high-end rendering that includes ray tracing, radiosity, complex textures and volumetric lighting. The test reports three scores: Animation (multitasking), Animation (interactive), and Rendering. The numeric scores represent the time it took to complete each section of the benchmark, in seconds, so lower scores are better.

I've found the SPECapc Lightwave 3D test to be an excellent indicator of overclock stability. In many cases, overclocked systems that will make it through every other benchmark here will crash in this test.

Here we see another application that Virtu can't handle, and another non-gaming application that benefits greatly from a discrete graphics card....at least for animation, where the Radeon 6850 configuration runs in less than half the time of the iGPU configuration. Overclocking the COre i7 2600k helps tremendously in the animation tests, more than doubling the overall performance.

The raw rendering test apparently uses only the processor, and here we see another example of the Z68 chipset-based motherboard beating the P67 system. Overclocking the Z68 system, though, only nets a performance gain of 12%, significantly smaller than we've seen in the other tests.

Street Fighter IV Benchmark

Street Fighter IV uses a new, built-from-scratch graphics engine that enables CAPCOM to tune the visuals and performance to fit the needs of the game, as well as run well on lower-end hardware. Although the engine is based on DX9 capabilities, it does add soft shadows, High Dynamic Range lighting, depth of field effects, and motion blur to enhance the game experience.

The game is multi-threaded, with rendering, audio, and file I/O all running in different threads. The development team has also worked to maintain a relatively constant CPU load in all parts of the game so that on-screen performance does not change dramatically in different game scenarios.

That said, the results are...unexpected. Luci Virtu kicks in in i-Mode to provide excellent performance, but overclocking the Intel Core i7 2600K processor adds virtually nothing to the performance. I'd guess this means that the frame rates in either case are GPU-limited, and that we would probably see more distinction in the results with a more powerful graphics card.

Blender

Blender is an open-source, free content creation suite of 3D modeling, rendering, and animation capabilities. Originally released in 2002, it's available in versions for Mac OS X, Windows, Linux, and several Unix distributions. It supports rigid and soft-body objects and can handle the draping and animation of cloth, as well as the rendering and animation of smoke, water, and general particle handling.

Our Blender test renders multiple frames of an animation of a chunk of ice, with translucency and reflections. Rendering of this model uses ray-tracing algorithms.

From these results it's obvious that Blender processes are entirely CPU based, with no work done on the GPU. The overclocked configuration is 27% faster.

P8Z68-V Pro Overclocking

The Cougar Point/Sandy Bridge platform brings major changes to the overclocking process. Here are the bullet points:

• Overclocking by increasing the base clock is no longer an option.
• Overclocking by increasing the CPU's base multiplier is no longer an option.
• Only the P67 and Z68 chipsets support CPU overclocking at all.

Intel's new chipsets derive almost every clock on the motherboard from the base clock (BCLK) frequency. This makes board design simpler and more reliable, but it also means that raising the base clock raises other clocks on the system...like, say, the PCI-E slot clocks, the SATA clock, and so forth. What this means in practice is that you'll be lucky to raise the BCLK as much as 5MHz without crashing your system. An overclocking mechanism enthusiasts have used for more than a decade is consigned to the dust bin of history.

Intel compensates for this by giving all Sandy Bridge processors unlocked multipliers: K-series processors get "fully unlocked" multipliers with no limits, while non-K series processors are "limited unlocked" CPUs that can only have their multipliers increased by a maximum of 4. All Sandy Bridge processors have fully unlocked video cores, RAM multipliers, and power settings, so you can tweak your RAM and on-board video with any motherboard.

You overclock a Sandy Bridge CPU by increasing the Turbo multiplier: that is, the one the CPU uses to automatically increase the clocks speed of its cores under load. If you raise the multiplier on a Core i7 980X Extreme chip, you're increasing its speed in all situations: idle and load. Raising the multiplier on a Sandy Bridge processor only raises the speed it will ramp up to under load; its idle speed remains the same. While this might seem limiting, in practice it works really well, since Turbo Boost is very, very good at deciding when to ramp up the clock speeds, and you benefit from dramatically reduced power consumption in low-load situations. Initially I didn't like this new overclocking mechanism but have come around after a few months' experience with it, and the older mechanisms now seem primitive. Since most of the overclocking mechanisms are built into the chip, the motherboard itself becomes less of a factor in overclocking than it was in the "raise the BCLK" days. Benchmark Reviews has published an in-depth article on Sandy Bridge overclocking.

ASUS provides a number of automatic overclocking mechanisms in the P8Z68-V Pro motherboard: you can start an auto overclock session directly from the UEFI BIOS, or take more control with ASUS' Turbo V Evo software. I'd recommend the latter for overclocking beginners: it generally achieves very stable results with good performance increases with almost no effort on the part of the user. However, so far, no automatic overclock mechanism can achieve the results of hand-tweaking. Still, the Turbo V Evo utility is very useful for experimenting with overclocking since it can make all the changes "live" while in Windows, without having to reboot each time as you do with settings changes in the BIOS.

In the "A.I. Tweaker" section of the BIOS, I achieved my best results with a BCLK of 103MHz and an "all cores" multiplier of 48, resulting in a final Turbo Boost overclock of 4.94GHz.

Try as I might, the magical 5GHz mark remained just out of reach. Since you can specify different overclocks on a "number of cores in use" basis, given more time I probably could have reached 5GHz in a single-core situation, but under Windows 7 there's never only going to be a single core in use, so the time spent at 5GHz would have been minimal. And given the amazing performance at 4.94GHz with all cores, I'm not too disappointed. This is 200MHz higher than I was able to get with my previous 2600K overclocking experiments with ASUS' P8P67 EVO motherboard.

You do have to be careful about one thing: with older processors, you knew your overclock failed when your system crashed. Sandy Bridge CPUs, on the other hand, are very clever about automatically reducing their clock speed when the CPU core temperature gets too high. You might think that overclock is working perfectly, but behind the scenes your processor is clocking itself down when things get too hot. Keeping a utility like CPU-Z open during your stress tests will let you see the core speed "live" so you'll know if this happens.

This overclock represents a 29% overclock from the standard 3.8Ghz Turbo Boost frequency, and applies to all four cores under load rather than the single core the stock 3.8Ghz applies to. This performance differential was reflected in the benchmarks. This is the highest "on air cooling" frequency I've seen with an Intel quad-core processor.

Z68 Motherboard Final Thoughts

The Intel Z68 chipset really brings Sandy Bridge processors into their full-featured birthright. The intial Cougar Point chipsets all hobbled the new CPUs in one way or the other: you couldn't use the integrated GPU, or you couldn't overclock. The Z68 removes these arbitrary restrictions, and along with Lucid's Virtu, enables new options in system configuration.

Lucid (formerly LucidLogix) originally came onto the enthusiast scene with their "Hydra" chip that promised vendor-independent multi-GPU scaling, i.e. the ability to use multiple ATI and NVIDIA cards in the same system, combining their performance. Hydra never worked as well as Lucid had hoped, although in some situations the performance gains could be significant. While Lucid's "Virtu" GPU virtualization software still has some rough edges— you must manually designate programs you want it to apply to, and not all programs can be so designated— but within these relatively minor constraints it works very well, imposing roughly a 5% performance penalty as compared with a "native" Radeon 6850 in my testing, and saving a significant amount of power when the performance of the discrete video card isn't needed. Remember, though, that multi-GPU setups cannot benefit from Virtu's i-Mode and its power-saving features. Perhaps NVIDIA's forthcoming Synergy will enable power savings for NVIDIA SLI setups.

Even without Virtu, you can connect two monitors (one to the VGA port and one to the HDMI port) to the motherboard while still using monitors connected to a separate graphics card: four monitors total with only one card! While this isn't the same as AMD Eyefinity (you wouldn't get decent 3D performance on the monitors connected to the motherboard in this mode), it's still a nice option for some setups.

When speaking with an ASUS representative about this motherboard, I was asked if there was anything I didn't like about the board, or any improvements I could suggest. While the board doesn't come with some of the extra features of ASUS' "Extreme" and "Formula" level motherboards (but I'm sure we'll see fancier Z68 motherboards from ASUS), I don't think most of those features matter much any more. Voltage read points for extreme overclockers? Almost irrelevant with the advent of ultra-accurate digital power systems. External overclocking or status panels? With ASUS' BT Go! feature, my iPhone does more than these ever could. Extra fans for motherboard chipsets? Not needed with the cool-running Cougar Point silicon. On-board POST display? OK, I'll take that one...

The features that really matter are there: evolved versions of ASUS' TPU and EPU processors; more overclocking options than I can really count, native USB 3 header with rear-panel breakout for cases without USB 3 support, four SATA 6G and four USB 3 ports, and nifty things like MemOK!, where pressing a single button will reset your memory to guaranteed-bootable settings, and AI Charger, and probably more stuff I forgot to mention- this motherboard has so many features and capabilities that there simply wasn't time to get to them all for this review.

I'd prefer more PCI-E lanes, but that's really up to Intel, not ASUS...but maybe a "P8Z68 Extreme" board could incorporate an NF200 chip! Really, though, the only things I'd change about this board's hardware are:

• Use DIMM sockets with latches on both sides. Originally, the single-latch sockets were designed to clear a large video card in the first slot, but unless someone makes a really long PCI-E x1 card, this isn't a consideration for this board. The single latch design makes it possible to have memory not fully inserted in the slot; with a dual-latch design, you know it's right if you can close both latches.
• Ditch the middle PCI slot and replace it with a PCI-E x4.

But that's all I've got. This board is the perfect platform for any enthusiast looking to build a high performance Sandy Bridge system. The features and performance of this motherboard with a Core i7 2600K processor are so compelling that the X58 platform, for all its extra PCI-E lanes, available hexacore processors, and triple-channel memory system, just doesn't seem very relevant any more. And I've heard from an industry insider that it's very likely that the forthcoming Ivy Bridge processors, whose 22nm process and 3D transistors will enable another substantial jump in performance (although I discount reports that desktop Ivy Bridge processors will be able to run on two "AA" batteries and be fast enough to rip holes in spacetime) will be able to run on Z68 platforms with nothing but a BIOS upgrade. It's a rumor, true, but still...

ASUS P8Z68-V Pro Conclusion

Although we strive to be as objective as possible, any review will reflect to some extent the perceptions and biases of the reviewer. Also, keep in mind that the computer market is very volatile, and that today's killer super product can easily become yesterday's also-ran as the market competition changes. Don't base a purchase decision solely on this review, but use it as part of your research.

ASUS is a name high on the list of many enthusiasts, and products like the ASUS P8Z68-V Pro are why. This isn't even one of ASUS' "high end" boards, and it's stuffed with so many features that there wasn't time to review them all. (But I cover Lucid Virtu and Intel Smart Response technologies in detail separate articles.) I could go on for pages more about the details of ASUS' EPU and TPU, or the BT Go! feature, or how well the various automatic overclocking mechanisms work. But although I couldn't cover them all, trust me when I say that they do work, and work very well indeed. Back in the dawn of personal computing, one magazine reviewed Apple's "MacPaint 2.0" software and concluded that it was a "work of art for artists", and although it may seem silly to rhapsodize about a motherboard, that's what came to mind when I sat back after days of benchmarking and working with of this board.

The performance of this board was excellent. It was fractionally faster at stock clock speeds than the similar ASUS P8P67 board, and I was able to take my Core i7 2600K processor 200MHz higher than I could with the older board.

Appearance is always a subjective matter. The P8Z68 Pro doesn't have the in-your-face colors and throbbing LED-lit logos of ASUS "Extreme", "Maximus", or "Formula" motherboard lines; its somewhat fanciful heat sinks are its concession to bling. But with excellent component layout and attractive colors, it'll look good in any windowed case.

Although this was a pre-production board, there was nothing on it to indicate that it was anything other than a standard model. All the electronic components lined up neatly and the silk-screened lettering was sharp and clear. The multi-phase digital power system might seem like overkill (do we really need 12 phases?), but that's what lets you reach those amazing overclocks with high stability.

Functionally, this board is a standout. ASUS reserves some features for its top-end boards, but voltage measuring points, dual BIOS chips, chipset fans and the like really wouldn't add anything useful to this board's smorgasbord of features. I'd prefer ASUS use DIMM sockets with retaining latches on both sides, and a POST code display would be nice, but that's about all I can think of to add.

At a price of $209.00, this board is about $30 more than ASUS' equivalent P67 Express-based motherboard. If that's enough money to make a difference for you, skip a few meals and get this board instead. This price represents an excellent value.

If you've bought a P67 or H67 board, the very existence of the P8Z68-V Pro might frustrate you (perhaps you can sell your existing motherboard). If you're in the market for a Sandy Bridge motherboard, this is about the best you can get right now, although I'm sure we'll see a P8Z68 Extreme or something like it soon.

Pros:

+ Can use integrated Sandy Bridge video and a discrete video card
+ Intel Smart Response technology boosts disk performance
+ EPU, TPU, and 12-phase power enable high and stable overclocks
+ Four SATA 6G and four USB 3.0 ports
+ Excellent UEFI BIOS implementation.

Cons:

- Single-latch DIMM sockets. I hate those.
- Virtu software still has some rough edges
- NVIDIA Synergy not available yet
- Paucity of PCI-E lanes

Ratings:

• Performance: 9.5
• Appearance: 8.5
• Construction: 9.0
• Functionality: 9.75
• Value: 9.25

Final Score: 9.2 out of 10.

Excellence Achievement: Benchmark Reviews Golden Tachometer Award.

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