Load testing the PSU

Load testing the PSU

Testing a power supple these days always is a bit of a challenge at hand. I mean without professional load testers it's pretty hard to stress a power supply of this class and actually measure its behavior.

Our first check is with a simple cheapo power supply tester, we monitor voltages quickly and check if all rails are working. All good here.

The test setup

So for our load test here's what we did. We emulate real world usage. We take a rather old thus energy hungry Intel P55 based Quad SLI compatible motherboard, armed it with a GeForce GTX 590 card (card has two GPUs). We combined the P55 motherboard with a Core i7 870 processor overclocked to 3.8 GHz. The system, well have a look:

These are the components used:

• eVGA P55 Classified SLI motherboard (has high power consumption and an NF200 chip)
• Core i7 870 (overclocked to 3800 GHz) 20x190 BLCK at 1.4 Volts
• 1x GeForce GTX 590 primary (2 GPUs)
• 4 GB Memory DDR3 @ 1520 MHz
• OCZ Vertex 2 SDD x1

Now with a setup like this, many years ago we'd reach 500~550 Watts power consumption as PSUs where not that efficient. But with power supplies getting so much more efficient these days, even that proves to be a very hard task to accomplish. So above our graphics card setup. Now on the software side of things it is time to give the PC a decent beating. Remember our focus remains PSU efficiency. We now take some other power supplies and start testing / comparing: 

Looking at efficiency is really simple, we apply the same load on several power supplies, from old to new. We look at the powered off status, windows IDLE status, productivity mode (we stress the CPUs) and during gaming. The lower the Wattage, the more efficient.

The best indicator for good efficient power consumption is by looking at the game test. As you can see the Corsair RM 650 actually consumes very little power. Judging from the results its amongst the more  energy efficient model we have tested to date.

Powered off most PSUs consume roughly 0.4 to 0.5 Watt. Half a Watt, which is great.

With the computer powered on and in absolute IDLE we can notice that most PSUs these days stay close to each other. In terms of  idle wattage with a 2~3 Watt difference. So let's zoom in at load testing.

When we focus solely on CPU productivity mode load for a second we see that the PSU draws 274 from the wall socket which makes the Corsair RM 650 amongst the better and efficient PSUs tested. Only platinum is a nothch better. Let's increase load a little though:

When we focus solely on gaming load, we see that the PSU draws 460W from the wall socket, that's really good, merely 10 Watts power draw away from Platinum and smack-down in the middle of other Gold PSUs.