Load Tests

We conducted several tests with this power supply, as described in the article Hardware Secrets Power Supply Test Methodology. All the tests described below were taken with a room temperature between 46° C and 48° C. During our tests the power supply temperature was between 51° C and 54° C.

First we tested this power supply with five different load patterns, trying to pull around 20%, 40%, 60%, 80%, and 100% of its labeled maximum capacity (actual percentage used listed under “% Max Load”), watching how the reviewed unit behaved under each load. In the table below we list the load patterns we used and the results for each load.

Since this power supply has only one +12V rail this time we connected all connectors from the power supply together on the +12V1 input from our load tester.

If you add all the power listed for each test, you may find a different value than what is posted under “Total” below. Since each output can vary slightly (e.g., the +5 V output working at +5.10 V), the actual total amount of power being delivered is slightly different than the calculated value. On the “Total” row we are using the real amount of power being delivered, as measured by our load tester.

Input Test 1 Test 2 Test 3 Test 4 Test 5
+12V1 5 A (60 W) 8 A (96 W) 14 A (168 W) 16 A (192 W) 18 A (216 W)
+5V 2 A (10 W) 8 A (40 W) 10 A (50 W) 18 A (90 W) 24 A (120 W)
+3.3 V 2 A (6.6 W) 8 A (26.4 W) 10 A (33 W) 16 A (52.8 W) 23 A (75.9 W)
+5VSB 1 A (5 W) 1 A (5 W) 1 A (5 W) 1.5 A (7.5 W) 2 A (10 W)
-12 V 0.5 A (6 W) 0.5 A (6 W) 0.5 A (6 W) 0.5 A (6 W) 0.8 A (9.6 W)
Total 87.8 W 174.6 W 262.9 W 348.8 W 431.5 W
% Max Load 20.4% 40.6% 61.1% 81.1% 100.3%
Result Pass Pass Pass Pass Fail
Voltage Stability Pass Pass Pass Pass Fail
Ripple and Noise Pass Pass Pass Pass Fail
AC Power 115 W 227 W 350 W 498 W Fail
Efficiency 76.3% 76.9% 75.1% 70.0% Fail

When we tried running test number 5, the power supply wouldn’t turn on, showing us that its over power protection (OPP) was in action and configured at a value that was lower than the power supply maximum capacity.

So we tried to change the configuration we had set for test number five to try to see how much power we could really pull from this unit. Starting from test number four, the maximum we could do was to increase one amp at +3.3 V from 16 A to 17 A, making the power supply to deliver only around 355 W (under this configuration it was pulling 510 W from the wall, so efficiency was 69.6%). Any other configuration we tried above that the power supply would work outside its specs, especially noise.

At test number four noise level for +12 V was 83.4 mV, for +5 V was 35 mV and for +3.3 V was 25.6 mV. By just increasing one amp at +3.3 V as we explained, noise level at +12 V jumped to 117 mV, at +5 V jumped to 50 mV and at +3.3 V stayed at 31.6 mV. As you can see these number are already touching the noise maximum level (120 mV for +12 V and 50 mV for +5 V and +3.3 V).

When we tried increasing one amp at +12 V noise jumped to 190 mV and skyrocket to 680 mV when we tried pulling 18 A from it – and, remember, according to the power supply label +12 V could deliver 18 A.

The conclusion is that according to our methodology Thermaltake Purepower 430 W NP isn’t a 430 W power supply, but a 350 W model! We also could only pull 16 A from its +12 V output, while the label says the limit is 18 A.

On the other hand, this power supply has its over power protection (OPP) circuit in action, which prevented this power supply from burning when we pulled more power that it could handle – what didn’t happen with Huntkey Green Star 450 W, which is also a power supply labeled at 450 W that can only deliver 360 W.

Below you can see noise level when we were pulling 355 W from this power supply.

Thermaltake Purepower 430 W NPFigure 15: Noise level at +12 V with power supply delivering 355 W.

Thermaltake Purepower 430 W NPFigure 16: Noise level at +5 V with power supply delivering 355 W.

Thermaltake Purepower 430 W NPFigure 17: Noise level at +3.3 V with power supply delivering 355 W.

Voltage regulation during our tests one through four was excellent, with all outputs within 3% of their nominal voltages – ATX specification defines that all outputs must be within 5% of their nominal voltages (except on -12 V where the limit is 10%).

This power supply provided efficiency below 80%, reaching 70% when we pulled the maximum about of power it could deliver – 350 W. Definitely there are better products around. Kingwin ABT-450MM, for example, is a competing cheap low-end power supply that could maintain an efficiency above 80% when pulling 40% and 60% of its load (i.e., between 180 W and 270 W).

Short-circuit protection was tested and was working just fine.

This power supply fans run very slowly when the power supply is cold and they started spinning faster as soon as the power supply reached 28° C, with an obvious increase on the noise generated, but not to the point we would categorize as disturbing.


Gabriel Torres is a Brazilian best-selling ICT expert, with 24 books published. He started his online career in 1996, when he launched Clube do Hardware, which is one of the oldest and largest websites about technology in Brazil. He created Hardware Secrets in 1999 to expand his knowledge outside his home country.