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

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 the behavior of the reviewed unit under each load. In the table below, we list the load patterns we used and the results for each load.

If you add all the powers listed for each test, you may find a different value than what is posted under “Total” below. Since each output can have a slight variation (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. In 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 both were connected to the power supply single +12 V rail (the EPS12V connector was installed on the +12VB input).

 Input Test 1 Test 2 Test 3 Test 4 Test 5 +12VA 3 A (36 W) 6.5 A (78 W) 9.5 A (114 W) 13 A (156 W) 16 A (192 W) +12VB 3 A (36 W) 6.5 A (78 W) 9.5 A (114 W) 13 A (156 W) 16 A (192 W) +5V 1 A (5 W) 2 A (10 W) 4 A (20 W) 5 A (25 W) 7 A (35 W) +3.3 V 1 A (3.3 W) 2 A (6.6 W) 4 A (13.2 W) 5 A (16.5 W) 7 A (23.1 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) 0.5 A (6 W) Total 89.4 W 180.3 W 268.9 W 361.3 W 450.1 W % Max Load 19.9% 40.1% 59.8% 80.3% 100.0% Room Temp. 44.4° C 45.2° C 45.5° C 46.2° C 46.4° C PSU Temp. 45.2° C 45.3° C 45.8° C 45.9° C 46.2° C Voltage Stability Pass Pass Pass Pass Pass Ripple and Noise Pass Pass Pass Pass Pass AC Power 105.1 W 208.4 W 314.0 W 430.7 W 553.3 W Efficiency 85.1% 86.5% 85.6% 83.9% 81.3% AC Voltage 117.7 V 117.5 V 117.2 V 115.7 V 114.4 V Power Factor 0.927 0.940 0.954 0.964 0.978 Final Result Pass Pass Pass Pass Pass

The Cooler Master GX 450 W can really deliver its labeled wattage at high temperatures. During our test five, however, the unit shut down from time to time due to its over temperature protection kicking in (this protection was available, as we could clearly see by the presence of two thermal sensors, one for this circuit and one for the fan circuit).

Efficiency was high, between 81.3% and 86.5%, which was a great surprise since this unit has only the standard 80 Plus certification.

Voltage regulation was very good, with all positive voltages within 3% of their nominal values, except for the +5 V output during test one (but it was still inside the proper range; the -12 V output was outside this tighter regulation but was still inside the proper range as well). This means that voltages were closer to their nominal values than required by the ATX12V specification, which says positive voltages must be within 5% of their nominal values and negative voltages must be within 10% of their nominal values.

Noise and ripple levels were always below the maximum allowed. At +5 V and +3.3 V they were extremely low, while on +12 V they were above what we’d like to see to consider this unit impeccable but still below the maximum allowed. Below you can see the results for the power supply outputs during test number five. The maximum allowed is 120 mV for +12 V and -12 V outputs, and 50 mV for +5 V, +3.3 V and +5VSB outputs. All values are peak-to-peak figures.

Figure 16: +12VA input from load tester during test five at 450.1 W (81.6 mV)

Figure 17: +12VB input from load tester during test five at 450.1 W (74.2 mV)

Figure 18: +5V rail during test five at 450.1 W (12.2 mV)

Figure 19: +3.3 V rail during test five at 450.1 W (7.4 mV)

If we tried to pull more than 450 W the unit would immediately shut down.

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.