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Load Tests

We conducted several tests with this power supply, as described in the article Hardware Secrets Power Supply Test Methodology.  

This time we made more detailed tests, starting from 85 W and increasing the load little by little until we could see the maximum amount of power we could extract from the reviewed unit.

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.

The +12VA and +12VB inputs listed below are the two +12 V independent inputs from our load tester. During this test the +12VA input was connected to the power supply “+12V1” rail, while +12VB was connected to the power supply “+12V2” rail (EPS12V connector).

Input Test 1 Test 2 Test 3 Test 4 Test 5
+12VA 3 A (36 W) 3.5 A (42 W) 4.5 A (54 W) 5.5 A (66 W) 6.25 A (75 W)
+12VB 2.5 A (30 W) 3.25 A (39 W) 4 A (48 W) 5 A (60 W) 6 A (72 W)
+5V 1 A (5 W) 1 A (5 W) 1.5 A (7.5 A) 1.5 A (7.5 A) 2 A (10 W)
+3.3 V 1 A (5 W) 1 A (5 W) 1.5 A (4.95 W) 1.5 A (4.95 W) 2 A (6.6 W)
+5VSB 1 A (5 W) 1 A (5 W) 1 A (5 W) 1 A (5 W) 1 A (5 W)
-12 V 0.5 A (6 W) 0.5 A (6 W) 0.5 A (6 W) 0.5 A (6 W) 0.5 A (6 W)
Total 84.0 W 98.6 W 123.5 W 146.8 W 171.5 W
% Max Load 14.0% 16.4% 20.6% 24.5% 28.6%
Room Temp. 45.5° C 44.2° C 41.5° C 40.7° C 40.4° C
PSU Temp. 48.1° C 47.5° C 47.2° C 46.9° C 46.9° C
Voltage Regulation Pass Pass Pass Pass Pass
Ripple and Noise Pass Pass Pass Pass Pass
AC Power 121.3 W 137.1 W 166.1 W 192.9 W 223.4 W
Efficiency 69.2% 71.9% 74.4% 76.1% 76.8%
AC Voltage 112.5 V 111.9 V 111.2 V 110.7 V 110.8 V
Power Factor 0.633 0.644 0.66 0.67 0.684
Final Result Pass Pass Pass Pass Pass
Input Test 6 Test 7 Test 8 Test 9 Test 10
+12VA 7.5 A (90 W) 8.25 A (99 W) 9.25 A (111 W) 10 A (120 W) 11 A (132 W)
+12VB 7 A (84 W) 8 A (96 W) 9 A (108 W) 10 A (120 W) 11 A (132 W)
+5V 2 A (10 W) 2.5 A (12.5 W) 2.5 A (12.5 W) 3 A (15 W) 3 A (15 W)
+3.3 V 2 A (6.6 W) 2.5 A (8.25 W) 2.5 A (8.25 W) 3 A (9.9 W) 3 A (9.9 W)
+5VSB 1 A (5 W) 1 A (5 W) 1 A (5 W) 1 A (5 W) 1 A (5 W)
-12 V 0.5 A (6 W) 0.5 A (6 W) 0.5 A (6 W) 0.5 A (6 W) 0.5 A (6 W)
Total 197.3 W 221.8 W 244.8 W 269.3 W 291.7 W
% Max Load 32.9% 37.0% 40.8% 44.9% 48.6%
Room Temp. 41.5° C 42.8° C 44.0° C 43.0° C 43.9° C
PSU Temp. 46.9° C 47.3° C 47.9° C 48.8° C 49.9° C
Voltage Regulation Pass Pass Pass Pass Pass
Ripple and Noise Pass Pass Pass Pass Pass
AC Power 255.4 W 286.4 W 315.5 W 347.4 W 376.6 W
Efficiency 77.3% 77.4% 77.6% 77.5% 77.5%
AC Voltage 110.0 V 109.8 V 108.5 V 108.2 V 108.2 V
Power Factor 0.689 0.699 0.706 0.711 0.715
Final Result Pass Pass Pass Pass Pass
Input Test 11 Test 12 Test 13 Test 14 Test 15
+12VA 12 A (144 W) 13 A (156 W) 14 A (168 W) 15 A (180 W) 16 A (192 W)
+12VB 11.75 A (141 W) 12.75 A (153 W) 13.5 A (162 W) 14.5 A (174 W) 15.5 A (186 W)
+5V 3.5 A (17.5 W) 3.5 A (17.5 W) 4 A (20 W) 4 A (20 W) 4.5 A (22.5 W)
+3.3 V 3.5 A (11.55 W) 3.5 A (11.55 W) 4 A (13.2 W) 4 A (13.2 W) 4.5 A (14.85 W)
+5VSB 1 A (5 W) 1 A (5 W) 1 A (5 W) 1 A (5 W) 1 A (5 W)
-12 V 0.5 A (6 W) 0.5 A (6 W) 0.5 A (6 W) 0.5 A (6 W) 0.5 A (6 W)
Total 315.9 W 338.3 W 362.8 W 384.3 W 410.5 W
% Max Load 52.7% 56.4% 60.5% 64.1% 68.4%
Room Temp. 44.3° C 45.7° C 47.4° C 48.6° C 48.8° C
PSU Temp. 50.8° C 51.9° C 53.6° C 45.8° C 42.8° C
Voltage Regulation Pass Pass Pass Pass Pass
Ripple and Noise Pass Pass Pass Pass Pass
AC Power 409.0 W 439.0 W 472.0 W 504.0 W 542.0 W
Efficiency 77.2% 77.1% 76.9% 76.3% 75.7%
AC Voltage 108.1 V 107.8 V 107.5 V 107.4 V 106.5 V
Power Factor 0.717 0.718 0.723 0.727 0.730
Final Result Pass Pass Pass Pass Pass
Input Test 16 Test 17 Test 18 Test 19 Test 20 Test 21
+12VA 17 A (204 W) 18 A (216 W) 19 A (228 W) 20 A (240 W) 21 A (252 W) 22 A (264 W)
+12VB 16.5 A (198 W) 17.25 A (207 W) 18.5 A (222 W) 19 A (228 W) 20 A (240 W) 21 A (252 W)
+5V 4.5 A (22.5 W) 5 A (25 W) 5 A (25 W) 5.5 A (27.5 W) 5.5 A (27.5 W) 6 A (30 W)
+3.3 V 4.5 A (14.85 W) 5 A (16.5 W) 5 A (16.5 W) 5.5 A (18.15 W) 5.5 A (18.15 W) 6 A (19.8 W)
+5VSB 1 A (5 W) 1 A (5 W) 1 A (5 W) 1 A (5 W) 1 A (5 W) 1 A (5 W)
-12 V 0.5 A (6 W) 0.5 A (6 W) 0.5 A (6 W) 0.5 A (6 W) 0.5 A (6 W) 0.5 A (6 W)
Total 432.6 W 456.4 W 479.6 W 500.6 W 521.4 W 547.3 W
% Max Load 72.1% 76.1% 79.9% 83.4% 86.9% 91.2%
Room Temp. 45.9° C 47.7° C 49.3° C 47.1° C 49.8° C 48.3° C
PSU Temp. 42.0° C 39.8° C 40.4° C 43.3° C 44.0° C 42.7° C
Voltage Regulation Pass Pass Fail on +12VB Fail on +12VB Fail on +12 V Fail on +12 V
Ripple and Noise Pass Pass Pass Pass Pass Pass
AC Power 575.0 W 611.0 W 650.0 W 684.0 W 727.0 W 785.0 W
Efficiency 75.2% 74.7% 73.8% 73.2% 71.7% 69.7%
AC Voltage 106.7 V 106.4 V 105.0 V 106.1 V 105.0 V 103.2 V
Power Factor 0.733 0.733 0.734 0.737 0.738 0.742
Final Result Pass Pass Fail Fail Fail Fail

The Cooler Master eXtreme Power Plus 600 W, like the 550 W model from the same series, can’t deliver its labeled wattage. The power supply immediately burned when we tried to run our 600 W load pattern (which would be our test number 22). Inspecting the power supply after it burned we discovered that the component that failed was one of the switching transistors. It is also very important to note that due to the huge difference between what we were supposed to see at the +12 V output and the actual voltage being delivered by the power supply (e.g., +11.25 V during test number 21), the total wattage delivered by the power supply was way lower than it should be. For instance, the load pattern used during test 21 was supposed to extract 575 W from the power supply, but it was delivering 547.3 W during this test.

Efficiency peaked at 77.6% during test eight, with the unit delivering around 245 W, and reached its lowest point at 69.2%, with the unit delivering 84.0 W.

Voltage regulation was bad, with the power supply not being able to keep the +12 V output inside its correct value from test 18 (480 W) on. Therefore, it is only safe to pull up to 450 W from this power supply – above this value this power supply can make your computer to run unstable.

Noise and ripple levels, on the other hand, were very low at all times. During test 21 we saw a noise level of 33 mV at +12VA, 36.4 mV at +12VB, 19.2 mV at +5 V, 15.2 mV at +3.3 V, 16.6 mV at +5VSB and 35.4 mV at -12 V. As we always point out, the limits are 120 mV for +12 V and -12 V outputs, and 50 mV for +5 V and +3.3 V outputs, and all numbers are peak-to-peak figures.

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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.