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 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 rail, we connected all power supply cables to 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 6 A (72 W) 13 A (156 W) 19 A (228 W) 25.5 A (306 W) 32 A (384 W)
+5V 1 A (5 W) 2 A (10 W) 4 A (20 W) 5 A (25 W) 6 A (20 W)
+3.3 V 1 A (3.3 W) 2 A (6.6 W) 4 A (13.2 W) 5 A (16.5 W) 6 A (19.8 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) 0.8 A (9.6 W)
Total 91.2 W 183.2 W 274 W 360.5 W 450.1 W
% Max Load 20.3% 40.7% 60.9% 80.1% 100.0%
Room Temp. 47.3° C 47.8° C 47.9° C 46.4° C 47.8° C
PSU Temp. 49.8° C 50.4° C 49.9° C 48° C 47.8° C
Result Pass Pass Pass Pass Pass
Voltage Stability Pass Pass Pass Pass Pass
Ripple and Noise Pass Pass Pass Pass Pass
AC Power 105 W 208 W 314 W 419 W 534 W
Efficiency 86.9% 88.1% 87.3% 86.0% 84.3%

The results for this power supply were simply unbelievable, especially when we think that this is supposedly an entry-level power supply. After reviewing a lot of lousy low-end power supplies it is a real joy to see an entry-level model that can not only deliver its rated power at 48° C, but also achieve an outstanding efficiency and a very low ripple and noise levels.

Efficiency is definitely one of the highlights of this product. Corsair says this power supply achieves a maximum 85% efficiency, but they are wrong – in a good way. The only time this power supply achieved efficiency BELOW 85% was when we pulled 450 W from it (84.3%). On all other tests efficiency varied between 86% and 88%. Amazing. Just to put things into perspective other entry-level power supplies can’t even reach 80% efficiency, and the ones that can they don’t reach 85%.

Voltage regulation during all our tests (including the overload tests we will present in the next page) was outstanding, 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, which was between -11.14 V and -11.42 V, depending on the load pattern. These numbers, however, are still inside the 10% margin that is set by the ATX spec for this output. Of course we always want to see values closer to the nominal voltage.

Noise and ripple was another highlight of this product. Corsair VX450W produces very little noise level, far below the maximum admissible. When we were pulling 450 W from it noise level at +12 V was 29.8 mV, at +5 V was 19.2 mV and at +3.3 V was 13.2 mV, as you can see on the screenshots below (just to remember, the maximum allowed values are 120 mV for +12 V and 50 mV for +5 V and +3.3 V; all these values are peak-to-peak values). We were really impressed by these results.

Corsair VX450W Power SupplyFigure 15: Noise level at +12V1 with power supply delivering 450 W.

Corsair VX450W Power SupplyFigure 16: Noise level at +5 V with power supply delivering 450 W.

Corsair VX450W Power SupplyFigure 17: Noise level at +3.3 V with power supply delivering 450 W.

Now let’s see if we could pull more power from this product.

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.