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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.  

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 our tests, the +12VA and +12VB input were connected to the power supply single +12 V rail (the EPS12V connector was installed on the +12VB input of our load tester).

Input Test 1 Test 2 Test 3 Test 4 Test 5
+12VA 5 A (60 W) 10 A (120 W) 15 A (180 W) 20 A (240 W) 23.75 A (285 W)
+12VB 5 A (60 W) 10 A (120 W) 15 A (180 W) 20 A (240 W) 23.75 A (285 W)
+5V 1 A (5 W) 2 A (10 W) 4 A (20 W) 6 A (30 W) 8 A (40 W)
+3.3 V 1 A (3.3 W) 2 A (6.6 W) 4 A (13.2 W) 6 A (19.8 W) 8 A (26.4 W)
+5VSB 1 A (5 W) 1 A (5 W) 1.5 A (7.5 W) 2 A (10 W) 2.5 A (12.5 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 139.4 W 267.4 W 393.6 W 542.9 W 649.9 W
% Max Load 21.4% 41.1% 60.6% 83.5% 100.0%
Room Temp. 47.2° C 45.2° C 45.8° C 47.6° C 48.0° C
PSU Temp. 45.9° C 46.6° C 47.0° C 47.9° C 49.1° C
Voltage Regulation Pass Pass Pass Pass Pass
Ripple and Noise Pass Pass Pass Pass Pass
AC Power 167.2 W 313.1 W 462.4 W 648.0 W 789.0 W
Efficiency 83.4% 85.4% 85.1% 83.8% 82.4%
AC Voltage 111.1 V 110.9 V 107.7 V 105.8 V 104.2 V
Power Factor 0.985 0.992 0.996 0.998 0.998
Final Result Pass Pass Pass Pass Pass

The XFX PRO 650 W passed our test with flying colors, being able to deliver its labeled wattage at high temperatures.

Efficiency was excellent, between 82.4% and 85.4%. This is great, because we are tired of seeing 80 Plus Bronze power supplies that can’t achieve 82% minimum at high temperatures, and the XFX PRO 650 W W can.

Voltage regulation was superb, with all voltages within 3% of their nominal values. The ATX12V specification allows voltages to be up to 5% from their nominal values (10% for the -12 V output). Therefore this power supply presents voltages closer to their nominal values than necessary all the time.

Noise and ripple levels were always extremely low. Below you can see the results for the power supply outputs during test number five. The maximum allowed is 120 mV for the +12 V and -12 V outputs, and 50 mV for the +5 V, +3.3 V, and +5VSB outputs. All values are peak-to-peak figures.

XFX PRO 650 W power supplyFigure 19: +12VA input from load tester during test five at 649.9 W (27.2 mV)

XFX PRO 650 W power supplyFigure 20: +12VB input from load tester during test five at 649.9 W (42.8 mV)

XFX PRO 650 W power supplyFigure 21: +5V rail during test five at 649.9 W (9.8 mV)

XFX PRO 650 W power supplyFigure 22: +3.3 V rail during test five at 649.9 W (9.6 mV)

Let’s see if we can pull even more from the XFX PRO 650 W.

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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.