![[H]ardOCP](/images/blank.gif){kind=small}
- Date:
- Monday , February 16, 2009
- Author:
- Paul Johnson
- Editor:
- Kyle Bennett
- Google +1
Entry Level Power Supply Roundup
Not everyone needs 1200 honking watts of power sitting in their new computer build. Not much has changed there. But what has changed is the enthusiast brands of power supplies that will now occupy the entry level PSU space. We have a few PSUs for you today that will not break the bank.
Load Testing
For those of you that are curious as to some of the reasoning and equipment behind our PSU testing program here at HardOCP, we have put together a living document that shares a lot of the behind the scenes of the program. The testing we are conducting today is exactly as described in that document and will begin with a range of loads tested at 120v input including our torture test and then move on to the same set of tests at 100v input but without the torture test.
120v Load Testing Results
100v Load Testing Results
Test #1 is equal to approximately 25% of the rated capacity of the Cooler Master eXtreme Power 500w at 45c. This makes Test #1 equal to 134w by loading the 12v rails to a combined 8a, the 5v rail to 3a, the 3.3v rail to 2a, the +5vsb to 2a, and the -12v to 0.5a. The results of Test #1 at both 120v and 100v see the DC output voltages at slightly above nominal values. The efficiency is coming in at 75.28% to 76.57% which is certainly a bit low in this day and age. The exhaust temperature however is only 1-2c above ambient which is good.
Test #2 is equal to approximately 50% of the rated capacity of the Cooler Master eXtreme Power 500w at 45c. This makes Test #2 equal to 247w by loading the 12v rails to a combined 15a, the 5v rail to 7a, the 3.3v rail to 5a, the +5vsb to 2a, and the -12v to 0.5a. Test #2 sees peak changes of 0.06v on the 12v rails and slightly lower values on the rest of the rails. The efficiency has moved up to 77.19% at 120v but has moved down to 74.62% at 100v. The exhaust temperature has jumped to 50c at 120v and 52c at 100v.
Test #3 is equal to approximately 75% of the rated capacity of the Cooler Master eXtreme Power 500w at 45c. This makes Test #3 equal to 363w by loading the 12v rail to 22a, the 5v rail to 11a, the 3.3v rail to 9a, the +5vsb to 2a, and the -12v to 0.5a. Test #3 again sees the 12v rails take the biggest beating as they show a peak change of 0.07v. The minor rails also drop here but not as much. The efficiency is down across the board as well hitting 75.31% at 120V and 72.89% at 100v. The only thing up here is the exhaust which moves up 2c from Test #2 levels in both tests.
Test #4 is equal to approximately 100% of the rated capacity of the Cooler Master eXtreme Power 500w at 45c. This makes Test #4 equal to 493w by loading the 12v rails to 30a, the 5v rail to 17a, the 3.3v rail to 15a, the +5vsb to 2a, and the -12v to 0.5a. In the final regular test the DC output voltages all drop again, but this time it is lead by the 5v rail which has dropped by 0.06v. The unit’s efficiency has also dropped to 71.24% at 120v and 70.43% at 100v. The exhaust temperature has jumped here by 8-9c over Test #3 peaking at 62c.
The Torture Test
The final component of our load testing involves our 8 hour torture test. This test is meant to simulate what gaming or hardware enthusiasts might encounter when they use their systems for extended periods of time under stressful conditions such as 3D gaming or long term stability testing and benchmarking. We do not suggest using your power supply at 100% loads for extended periods of time and our torture test does reflect this. We load the PSU being tested to ~80% of its rated capacity for 8 hours at a temperature of 45c. This is outlined in our testing methodology should you wish to have more information.
The Torture Test is equal to approximately 80% of the rated capacity of the Cooler Master eXtreme Power 500w at 45c. This makes Test #3 equal to 394w by loading the 12v rails to 24a, the 5v rail to 12a, the 3.3v rail to 10a, the +5vsb to 2a, and the -12v to 0.5a. At the end of the Torture Test we find that the Cooler Master eXtreme Power 500w is still running and in as good of shape as could be expected from the trends established in its regular load testing results. The DC output voltages are off of Test #3 levels slightly while the efficiency has also dropped below Test #3 levels. In the end though this was a good result given how much the unit was struggling in Test #4.
Transient Testing
The Transient Testing portion of this review marks the first revision to our living testing methodology. Readers can read more about this inclusion in our testing here in our methodology section, but briefly we will be examining the response of the power supply to a short duration load such as a RAID array spinning up or load change due to power draw from video cards etc. Ideally we would not see a deflection from the baseline voltage output when this occurs but that is simply not the case for the majority. We will be using the ATX12v specification for transient response as a guide.
The Transient Load Tester adds an additional 9.25A to the 12v rail for 10ms and an additional 3.75A to the 5v rail for 10ms at 25% total load and 50% total load.
Transient Load Testing Results
Test #1 is equal to approximately 25% of the rated capacity of the Cooler Master eXtreme Power 500w at 45c. This makes Test #1 equal to 122w by loading the 12v rails to a combined 7a, the 5v rail to 3a, the 3.3v rail to 2a, the +5vsb to 2a, and the -12v to 0.5a before the addition of the transient load. The results of Test #1 show a peak change of ~400mV when the 12v rail is loaded and ~120mV change when the 5v rail is loaded. During the 12v load an unloaded 12v rail shows a peak change of ~180mV while the 5v rail shows a peak change of ~60mV.
Test #2 is equal to approximately 50% of the rated capacity of the Cooler Master eXtreme Power 500w at 45c. This makes Test #2 equal to 234w by loading the 12v rails to a combined 14a, the 5v rail to 7a, the 3.3v rail to 4a, the +5vsb to 2a, and the -12v to 0.5a before the addition of the transient load. Test #2 shows a peak change of ~400mV when the 12v rail is loaded and ~100mV change when the 5v rail is loaded. During the 12v load an unloaded 12v rail shows a peak change of ~220mV while the 5v rail shows a peak change of ~60mV.
Load Testing Summary
The load testing results for the Cooler Master eXtreme Power 500w were decent overall, though a few items certainly did give away the designs age. The voltage regulation was good with the peak change on the 12v rails being just 0.17v over their entire capacity range. The Transient Load Testing results saw a peak 12v change of 400mV when loaded and a peak 5v change of 220mV when loaded. These values are more due to the fact that the loads presented in this test are a larger percentage of the unit’s DC output capacity than they are for bigger units more than age of the design. However, the efficiency which ranged from 71.24% to 77.19% at 120v is due to the units much older design as is the low PF readings. Overall though, the Cooler Master eXtreme Power 500w did pass all of our load testing, no matter its designs age, and that is surely something not every unit can claim even with the newest of designs.
