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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 this test, both inputs were connected to the power supply’s single +12 V rail. (The power supply’s EPS12V connector was installed on the +12VB input of the load tester.)

Input Test 1 Test 2 Test 3 Test 4 Test 5
+12VA 5 A (60 W) 10 A (120 W) 14.5 A (174 W) 19 A (228 W) 23.5 A (282 W)
+12VB 5 A (60 W) 10 A (120 W) 14 A (168 W) 19 A (228 W) 23.5 A (282 W)
+5 V 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) 1.5 A (7.5 W) 2 A (10 W) 2.5 A (12.5 W) 3 A (15 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 140.5 W 271.4 W 396.8 W 521.1 W 644.7 W
% Max Load 21.6% 41.8% 61.0% 80.2% 99.2%
Room Temp. 45.2° C 45.2° C 45.5° C 48.4° C 48.8° C
PSU Temp. 42.2° C 42.5° C 43.5° C 45.6° C 47.6° C
Voltage Regulation Pass Pass Pass Pass Pass
Ripple and Noise Pass Pass Pass Pass Pass
AC Power 168.4 W 318.5 W 468.6 W 625.0 W 789.0 W
Efficiency 83.4% 85.2% 84.7% 83.4% 81.7%
AC Voltage 115.9 V 114.5 V 113.1 V 111.7 V 110.2 V
Power Factor 0.985 0.99 0.995 0.997 0.997
Final Result Pass Pass Pass Pass Pass

On our tests, the XFX PRO 650 W XXX Edition presented efficiency between 81.7% and 85.2%, virtually matching the 80 Plus Bronze certification, which promises a minimum efficiency of 82% at light (i.e., 20%) and full loads, and 85% at typical (i.e., 50%) load. The efficiency at full load was a tad below the 82% promised by the 80 Plus Bronze certification. Tests for the 80 Plus certification are conducted at 23° C, while we test power supplies between 45° C and 50° C, and efficiency drops as temperature increases.

While the +12 V and +5 V outputs always presented values closer to their nominal values than required (3% regulation), voltage regulation could be better at +3.3 V and +5VSB, as you can see in the table below. Nevertheless, all outputs were inside the allowed range. The ATX12V specification states that positive voltages must be within 5% of their nominal values, and negative voltages must be within 10% of their nominal values.

Input Test 1 Test 2 Test 3 Test 4 Test 5
+12VA ≤ 3% ≤ 3% ≤ 3% ≤ 3% ≤ 3%
+12VB ≤ 3% ≤ 3% ≤ 3% ≤ 3% ≤ 3%
+5 V ≤ 3% ≤ 3% ≤ 3% ≤ 3% ≤ 3%
+3.3 V ≤ 3% ≤ 3% ≤ 3% +3.16 V +3.15 V
+5VSB ≤ 3% ≤ 3% +4.83 V +4.77 V +4.77 V
-12 V ≤ 3% ≤ 3% ≤ 3% ≤ 3% ≤ 3%

Let’s discuss the ripple and noise levels on the next page.

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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.