Load testing the PSU

Load testing the PSU

As you can see, we had 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.

So here's what we did. We emulate real world usage. We took a P55 Quad SLI compatible motherboard, armed it with a GeForce GTX 590 card (two GPUs per card).

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
• SDD x1

Now with a setup like this, two years ago we'd reach 500 Watts power consumption as maximum. But with power supplies getting more and 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. At 50% load it should be the most efficient (~94%), that's under a 425W load.

We now take two other power supplies: 

• The Tagan BZ PSU is dating from 2008, that was a close to 80% efficient product. We suspect roughly 75% though.
• The 2nd generation BFG 1200W EX was rated March 2009, here's where efficiency started to matter and it was rated roughly 80%~84 efficient.
• Today's tested Platimax is rated at 94% efficiency, the platinum certification requires it to be 92% efficient at 50% load.

Powered off all PSUs consume roughly 1-2 Watt. With the computer powered on and in absolute IDLE we can already see differences. The Platimax is the most energy efficient, compared to the Tagan it's already 15 Watt.

Once we stress the CPU cores we slowly put an average load on the PSU. Here again distinct differences in-between the "old" Tagan and Platimax, 21 Watts.

Gaming wise we put roughly 50% load on the Platimax PSU, and that's great as it's also the average power consumption for an enthusiast class PC these days. Roughly 450 to 500 Watt, there's quite a difference noticeable.

The BFG did not disappoint, but when released we already knew it was a top class PSU. But again when comparing a 2008 model PSU with this new Platinum certified PSU, that's where it matters, as there is a 39 Watt difference in wall socket power draw. And just for using a new PSU model.

We find this very interesting.

In suspend to RAM or hybrid power mode the Enermax platinum PSU kicks in nicely, we see roughly 2~3 Watt power consumption.