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Written by Olin Coles   
Friday, 16 April 2010
Table of Contents: Page Index
SSD Benchmark Tests: SATA IDE vs AHCI Mode
SSD Benchmark Differences
SSD Test Methodology
Indilinx: AS-SSD Performance
Indilinx: CrystalDiskMark
Indilinx: HD-Tune Speed
JMicron: AS-SSD Performance
JMicron: CrystalDiskMark
JMicron: HD-Tune Speed
SandForce: AS-SSD Performance
SandForce: CrystalDiskMark
SandForce: HD-Tune Speed
Final Thoughts and Conclusion

SSD Benchmark Tests: SATA IDE vs AHCI Mode

In a recent Benchmark Reviews technical article, SSD performance was tested in AHCI and IDE mode using only the HD-Tune software to produce results. It wasn't intentional, but our test results were flawed by this single-threaded benchmark tool, and our conclusion did not properly illustrate IOPS performance. In this article, Benchmark Reviews tests the latest JMicron, Indilinx, and SandForce SSDs using a combination of tools to illustrate the true difference between SATA IDE and AHCI-mode, and demonstrates how one SATA mode is better suited than the other.

Solid State Drive technology is unfamiliar to many consumers, and so long as there are different ways an SSD can operate there always be questions that need answering. Benchmark Reviews offers various SSD tests, but proving performance speeds and matching manufacturer claims is only part of the story. Each SSD processor has unique behaviors, with some working well with TRIM and offering improved performance in AHCI mode, while others include Garbage Collection (GC) and work best in IDE mode. In this article Benchmark Reviews demonstrates how SSDs are tested by the manufacturer, and illustrates how real-world performance is different for end-users.


When Benchmark Reviews first started testing SSD storage products two years ago, we discovered that there were just too many variables to alter benchmark results. For example, the exact same Solid State Drive may offer one specific write speed while connected to the Intel ICH10 controller, yet could operate up to 30% slower on Marvell or JMicron SATA controller. Additionally, immature driver software can further degrade performance, or optimized drivers can restore speeds. Complicating matters even more, SSD-specific firmware can add features and improvements, but may also reduce operational speeds.

Readers familiar with the new technology have learned to read reviews from as many sources as possible; which is exactly what we've been suggesting in our product conclusions for almost two years. Some websites don't use special drive conditioning tools such as DISKPART or Sanitary Erase, and other do. The same is true for SSD owner, which span from hardware enthusiasts to basic computer users. Benchmark Reviews has concentrated on including several different tools for realizing quantitative performance results for our articles, while other websites use real-world file transfers and application routines. It's all relative, subjective, and impossible to determine which method is best.

For this article, our tests will focus on three of the most widely used SSD processors from Indilinx, JMicron, and SandForce. Using the Intel ICH10 SATA-3.0 controller, our SSD tests will benchmark read and write performance speeds with pristine 'fresh' NAND conditions with Sanitary Erase (for Indilinx) and DISKPART with the 'clean all' command for drive conditioning. Operational IOPS performance will be tested in much the same way, and will reveal which SATA controller is best suited for SSDs.



# Microsoft AHCI Driver FlawGreg 2010-04-18 08:18
There appears to be a flaw in the Microsoft AHCI driver, large secondary hard drives (ex. 1TB) will disappear after the computer enters sleep mode. Installing the Intel RST driver 9.6 driver has solved the problem for a number of people including me.
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# Scope and purposeOlin Coles 2010-04-18 12:56
For those who have asked: I do not presently have any plans to add more tests of other SSDs into this article. The primary purpose was to illustrate the differences seen between AHCI and IDE, and not necessarily demonstrating the differences for every SSD controller. I didn't include Fusion-IO, RunCore, Micron, Toshiba, Marvell, Intel, Mtron, MemoRight, or PhotoFast... to name a few.
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# A Great ArticleRobert C 2010-06-25 23:09
Thank you for providing a comprehensive, informative, and useful article on SSD performance and testing. Although not the articles intent, I imagine SSD owners that cannot use them in AHCI mode will be pleased (relieved!) to see that SSD performance is not terribly compromised (IMO)in IDE mode. I don't understand why SSD manufactures have not offered any utilities that provide at least some of the information available in the testing software you used. I tried AS SSD Benchmark, and was pleased to verify (my first SSD) I am running in AHCI mode, my SSD's alignment is correct, and my scores were great relative to the data you provided in this and other SSD articles. In contrast to that, my SSD's manufacture has provided virtually no useful information or ways to get it. Thanks again and keep up the good work!
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# Hotfix for large drive resume from sleepDave_O 2010-07-30 04:49
This fixed the issue with my large SATA disk disappearing when resuming from sleep.
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# RE: SSD Benchmark Tests: SATA IDE vs AHCI Modeguest 2010-12-03 13:40
Well I experienced a 30-40MB jump in speed over IDE. Using a OCZ Vertex 2 60GB. I was already getting 230MB/s read and write, with buffered being slower if you can imagine. That jumped to 270MB/s when I went to AHCI, under sisoft. I didn't even have to run a bench to notice the difference. On bootup, win 7 didn't even get halfway through the logo animation before it reached the desktop. I'll have to run another test using file cache.
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# ThanksFred 2010-12-29 12:54
I came here trying to find whether I should use IDE or AHCI with a new Sandforce SSD and this article answered my question perfectly! Thanks for the great article :)
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# Bad article.Bas 2011-02-24 01:39
You focus on speed rather then access-time. I can assure you that the difference between 1ms (IDE) over 2ms (AHCI) has a far greater impact then the few kilobytes you gain in speed.
Ever tested SCSI versus SATA at the same RPM? Well there you will see exactly the benefit of access-times. Speed is rubbish when AT isn't good.
Test controllers on AT first, speed second, the picture will be a lot different in favor of IDE mode.
Same as with Internet, band-weight is nice, but if your ping is crap it won't be fast either.
You focus on the wrong points to measure a drive.
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# I forgot.Bas 2011-02-24 01:42
NCQ is not a feature you want on SSD!! As SSD has no spinning storage, but instant access, so NCQ is just an overkill as your access-times show.
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# Analogy is wrongBLJ 2011-03-22 03:43
The Ship IOPS / Bandwith analogy is just wrong.
it would be more like:
IOPS is the ship's speed, Bandwith is the cargo capacity.
If you want to build a small house, and you need parts that can be delivered by either:
1x Big slow ship, that has 100x the capacity required
1x Small fast ship, that has just the capacity required

you'll be able to start building your house sooner with the fast ship, as it will arrive sooner.
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# RE: Analogy is wrongOlin Coles 2011-03-22 05:52
It's an analogy; it's not wrong, it's just not the perfect.
Another would be to compare bandwidth and IOPS to a highway. Bandwidth determines the number of lanes, and IOPS determines the travelers.
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# Still not good enough..Bas 2011-03-22 08:43
As you also have access-time, that one determines how close the cars can run behind each other.
The lower the number the closer they can drive behind each other, also affecting the IOPS.
As such access-time is the most important number over all of them.
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# RE: Still not good enough..Olin Coles 2011-03-22 08:50
I wouldn't say access time is the most important number, because if one SSD had a .001ms access time with 100 IOPS it would be worse than a 1ms SSD with 100,000 IOPS.
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# Huh?Bas 2011-03-22 09:05
Do you know how important access-time really is? What you are saying now is rubbish.
IOPS can not be fast if your access-time is slow.
The access-time is the time the device needs to find the data and start delivering it.
There is no way on earth your IOPS can be high with a low access-time.
Sorry Olin, but you better find a new job if you don't understand the importance of access-time.
And yes I have read your article, and it's way too much focused on band-weight.
Typical mistake, why do you think SCSI drives are twice as fast as the fastest IDE drive at the same RMP and band-weight?
Exactly, it's the low access-time that causes this...not throughput.
Because of your wrong interpretation of access-time, I consider your entire article and conclusion as useless for anybody.
Do research on the matter, you will find I'm right.
Your IOPS versus Access-time is completely wrong.
IOPS means I/O operations per second, if your access-time is low it means it will do LESS I/O operations per second as it needs to wait for the device to access the data.
Do your research before writing rubbish as you make a fool of yourself.
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# RE: Huh?Olin Coles 2011-03-22 09:11
So in your heavily opinionated assessment, a SSD with relatively high access time cannot offer high IOPS? Explain how SandForce was able to offer a SSD with the same access times, but dramatically different IOPS. Also, do the math of my figure above.
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# Sr.James 2011-10-21 04:02
Bas, the only person making a fool of himself is you. Not only is your argument faulty (the data is right here in this article ... ) - your tone is that of an agitated 12 year old. Learn to control yourself and conduct proper research.

Practice ... preach ... honestly.
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# Why no benchmarks for AMD platformsJohnnyBravo43 2011-07-07 06:05
I see alont of SSD reviews, but they all reference Intel Platforms and Intel Drivers etc...
It would be nice to see some Tests/Reviews of Benchmarks that provided results for both camps ( Intel & AMD )
I would also be appreciative to see Microsofts AHCI Driver tested/included as well as AMD's ATI AHCI Driver tested/included. As well as the Marvell AHCI driver that is more commonly seen in AMD platforms verses what shows up or is seen in the Intel Platforms.....

Thanks for this review, but it is hard to apply what I have read to my AMD Platform which uses ATI AHCI Drivers &/or Microsoft AHCI Drivers if I use the MS Windows 7 generic AHCI driver......
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# Driver?Bas 2011-11-05 09:27
The drivers today are not the problem, systems are fast enough to eliminate the speed between them. Difference between CHIPS is far more important then driver testing.
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# bas and olin are both incorrectrarchimedes 2011-11-04 15:15
Both bas and olin have missed the mark here by trying to oversimplify the issues. There is no direct one-to-one relationship between or among IOPS, access time, and bandwidth. Too many factors intrude for such simple relationships. For truly independent IO's, access time can put an upper limit on IOPS, but more than a small percentage of IO's are logically and physically dependent. Depending on the intelligence of the drive and OS software in dealing with various forms of IO, huge differences in performance can arise. Depending on the page and block saturation in an SSD, writing the same file to that device can produce vastly different results, even in the absence pf interfering or block overlapping IO. Different fill methods for blocks and pages can cause what appear to be random changes in performance. Even in the simplest of cases with known algorithms, understanding these performance fluctuations can be complex.

If you would like to push a drive to the maximum performance in a real world situation, you should put a single large paging file on the drive and use programs that drive the paging rate as high as possible. When that settles down to a constant rate over time, then a measurement of paging rate will tell you what the maximum performance is in a real world situation. I am not sure that TRIM will actually improve performance in a busy drive, and it certainly loses the ability to recover any deleted file. A smart TRIM handling on a drive would queue the TRIM requests up and satisfy them when the drive is not otherwise busy, rather than giving them the priority they have under existing classification. TRIM could certainly help in a situation where the read to write ratio is high and the drive is not particularly busy, but this also would lessen the advantage the SSD has over a drive with a large built-in cache.

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# bas and olin are both incorrect continuedrarchimedes 2011-11-04 15:17
Unfortunately, we do not have a good way other than thruput to measure actual physical transfer rate. Normally, transfer time plus access time would determine the actual IOPS for any particular type and size of file, but SSD's are so extremely sensitive to page and block alignment on IO's that characterizing such beyond the simple, fully erased situation is basically impossible. The one thing that I will agree with bas on is that the tests in this review are not particularly meaningful. I'm not sure that even the relative difference between IDE and AHCI has much meaning. It is going to take some very intensive testing with some experimental software, specifically designed to test the devices in a consisten and repeatable manner that is more closely related to the real world to produce any meaningful comparisons of anything.
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# Where am I wrong?Bas 2011-11-05 09:23
Where am I wrong? AHCI adds commands to the protocol that are rubbish, like NCQ.
There is no point in doing NCQ as there is no rotation of the drive where command ordering is needed or even wanted.
NCQ has been proven to hinder the performance as it can stall the controller by making the computer WAIT before giving new commands.
SSD is a matrix and ordering is silly as all cells deliver data at the same speed, there is no ordering wanted to optimise the rotations in where data can be read.
But AHCI is still doing it, as such it lowers performance, and this can be noticed when using better benchmarks that can do proper I/O reading and writing combined with multiple commands at the same time. That benchmark has been here for ages, called ATTO.
Give ATTO a high command-que depth and see what happens, it will show the difference. As ATTO gives read and write speeds, for me it's the best harddisk/ssd benchmark on the planet when used properly.
Meaning VERY large Block-size and high Que-depth, then it gives pretty accurate numbers.
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# Where you are wrong?gadgetman! 2012-09-19 02:23
That would be your 'build one house' analogy...
That's only applicable in a single-threaded system.
Your modern PC is more akin to a large downtown reconstruction effort after Catrina...

Also, comparing the HDD with a big cargo ship...
On a large cargoship, unless your goods are all in one container, or all the containers with your goods have all been stacked on top of each other, they will need to unload some containers inbetween yours. Then probably reload the inbetween containers.

A better analogy would be a long freight-train carrying cargo containers that passes under a single crane that can lift containers off the wagons.
What is more effective?
1. Unloading the containers belonging to one customer(1, 15, 33, 7 - the last one was a recent addition that was fitted there after container 7 was removed on an earlier stop), then the next customer(4, 8, 12, 13, 14, 53)?
". Or to offload them in a sequential order?

Remember, the crane can only offload containers at a fixed speed, the train can only be moved forward or back at a low accelleration...
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# RE: SSD Benchmark Tests: SATA IDE vs AHCI Modebob 2011-12-30 12:45
TRIM works in both modes. Thank you for pointing that out.
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# RE: SSD Benchmark Tests: SATA IDE vs AHCI ModeJohn C. 2012-02-16 22:05
To add to Bas info--for those desktop users that use their computers for other things other than as internet servers, like burning CDs and DVDs etc...IDE mode for SATA controllers offers vastly improved CD/DVD writing performance. In AHCI mode my DVD burners do not seem to work properly when attempting to write. In IDE mode my DVD burners operate as they should. Until they perfect AHCI mode for other peripherals such as DVD burners on the SATA controller, I am sticking with IDE mode. There's not enough performance difference between IDE and AHCI to warrant putting up with the quirky DVD burner behavior in AHCI mode. Nuff said! If you run SATA burners and still like AHCI over IDE, then I've got some swamp land in Florida I'd like to sell you.
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# Need help guys.here_soon 2012-06-02 07:30
I can't have my HDD run in AHCI together with my SSD. It won't load the OS and keeps on crashing.
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# RE: Need help guys.Olin Coles 2012-06-02 07:31
That's because you didn't originally load the Windows (XP?) OS with AHCI enabled so it could install F6 drivers. You'll need to use IDE mode.
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# RE: RE: Need help guys.here_soon 2012-06-03 22:07
My HDD previously have Win7, so there's no way to get around this problem? A full reformat for the HDD is needed to run it in AHCI, am I right?
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# Switching from IDE to AHCI in BIOS causes renaming of Boot Drive by Windows 7Chris 2012-09-03 08:58
Gigabyte 990FXA-UD3
Vertex 3 120gb SSD
WD 1.5tb SATA2
A recent BIOS update added VRM MOS protection.
This disables access to the BIOS settings during POST .
If the Windows 7 based TouchBIOS utility is used, and the SATA type is changed from IDE to AHCI in CMOS and the system is rebooted. Windows renames the Boot drive from C:\ to E:\ and Windows Blue Screens during loading. Normally this wouldn't be a big problem, since the BIOS setting could be changed during POST. However, the VRM MOS protection forbids changing those settings during POST. The BIOS must be reflashed with a legacy BIOS (F6) or earlier, that does not have VRM MOS protection, in order to enable the IDE type support that Windows was installed with. I believe this VRM MOS protection is a standard part of the new types of BIOS required by Windows 8. So it must be enabled during OS installation or it could be lost
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# 4 Years LaterMLO 2014-02-11 10:53
You mentioned things could change as time and technology moves forward. Well it's now 4 years later. Maybe a revisiting of comparison benchmarks is in order?
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