|Antec TP3-650 Rev. A2 TruePower Trio 650W PSU|
|Reviews - Featured Reviews: Power|
|Written by Olin Coles|
|Wednesday, 27 September 2006|
Page 5 of 6
PSU Load Testing
I am very aware of what the more knowledgeable readers think about these power supply reviews: impractical and often useless. Power supplies are not like other computer components, where it is a simple matter of comparing the item to others in the same category. Power supply units offer many different variables, and each must be analyzed with unique tools. In the past, Benchmark Reviews has been guilty of the same thing its affiliates are guilty of: testing with a digital multimeter alone. For this reason alone, Benchmark Reviews will also discontinue posting affiliate reviews which do not properly test the power supply unit. So beginning now with this review, we are taking a corrected approach to testing PSU's.
PSU Test Equipment
Power Supply Test Methodology
Benchmark Reviews has researched the equipment necessary to complete the most thorough power supply unit review possible. We spent the time learning what it takes because the best possible PSU tests are what we want to give to our readers. But after discovering the prices on a programmable output DC power supply system, variable range load testing units, and a DC power analyzer (Oscilloscope), we felt that more than ten-thousand dollars worth of equipment would be far too cost prohibitive for testing a hundred-dollar power supply. So without compromising too much, we made a slightly less-expensive investment into a good quality Oscilloscope in order to test voltage power ripple and regulation. Together, the Oscilloscope and digital multimeter will offer readers the best measurement of power stability any review site could practically offer.
Our testing process is comprised of measuring the AC current ripple, and the DC voltage regulation. There are several key steps, all of which allow us to measure and record our readings using the identical methods for every test we perform. Consistent testing methods are key to obtaining comparable results.
At the start of every test, the Velleman PCSU-1000 Oscilloscope is calibrated to the PC-Lab2000SE software. After calibration is complete, the voltage on the 12V rails are measured and recorded with the Extech 450 digital multimeter to ensure comparable margin across all rails. Once the Velleman 60MHz probe has been grounded and attached to the 12V lead, our test system is powered on and left at the Windows logon screen for ten minutes.
Once this lightly-loaded idle warm up period is complete, the Velleman PCSU-1000 Oscilloscope was allowed to run for one minute measuring the AC power ripple. Then once ripple is recorded, the 12V DC voltage regulation is recorded after another minute.
After the results have been recorded from the light idle load, our test system then receives heavy load by utilizing the following tools: two console versions of the Folding @ Home client operate and task each CPU core to 100%, hard disks are stressed by benchmarking each with HD Tach RW, system memory (RAM) is given a stress test with Lavalys EVEREST, and ATITool scans for artifacts which forced the video card into high-power 3D mode. After ten minutes of heavy load the power supply is again measured, and the AC power ripple and 12V DC voltage regulation results are recorded.
Voltage Regulation Test Results
In the test results below, it will be necessary to explain what you are viewing. In each image, the power ripple is represented by the yellow trace line. While every DC power supply available to the retail market has some degree of measurable DC power regulation deviation, it is most important that there are only a few very minor changes to the expected voltage. Stable, well-regulated power is critical to system stability and hardware longevity.
The image above shows the 12V DC power regulation under light idle load, which measures 0.04V. Note that there are several minor differences above and below the 12V baseline, and only a few major changes in voltage level, all of which occur inside of a 1ms recording frame.
The waveform information above describes the actual measurements at light idle load. The maximum peak-to-peak distortion was 0.94V, which appears to come more from over-voltage than from under-voltage since the mean voltage is 12.25V.
Under heavy load, the Antec TP3-650 (Revision A2) has many minor differences in voltage which appear above 12V, and several major deviations occurring above and below the 12V baseline.
The Antec TP-650 A2 did not measure far from the idle readings when placed under heavy load. Most importantly, the power never dipped any lower than 11.81V, which means that even under heavy load there will sufficient power to uphold system stability.
Many of the power supplies we test here at Benchmark Reviews have DC voltage regulation measuring above the 12V baseline more often than below. For obvious reasons, the diversion from the 12V baseline with increased voltage is more preferred than below it since dropping too far under 12V will cause a system to power off or recycle. Plainly put, no power supply is ever perfectly centered at 12V DC; instead they most often maintain a DC mean voltage higher than they are regulated at.