Load Testing The PSU
Load Testing The PSU
Testing a power supply these days is always 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. A perfect score.
The Test Setup
So for our load test here's what we did. We emulate real world usage in this stage. We revert back to an older energy hungry Intel P55 based Quad SLI compatible motherboard, armed it with GeForce GTX 590 cards (each 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
Looking at efficiency is actually a simple thing to do, 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 IDLE power consumption is average to normal.
The best indicator for good efficient power consumption is by looking at the game test. As you can see the MasterWatt consumes power according in that Platinum and Titanium region power supplies. Powered off most PSUs consumes 0.2~0.3 Watt, the switches really off so it definitely complies with ErP standards. But 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 261W from the wall socket side. As you can see, the efficiency is smack in the upper class of efficiency. For this kind of certified PSU, that's pretty spot on, for a such a high level 1000W+ model, that's actually impressive as typically at 50% these units are the most efficient.
Above a very simple test, once we power down the PC; it can still consume power. Following EU legislation your PSU and Motherboard combo should remain below 0.2 Watt in sleep or power down mode. Over the years this has improved quite a bit. To achieve these levels you will need to enable EuP mode in the BIOS of your motherboard.
For the following step we measure the PC power consumption in IDLE. Mind you this system is DATED hence the ridiculous high overall IDLE power consumption. Current PCs all hover in the 160~180 Watt range when in IDLE (with a dedicated GPU installed).
When we focus solely on gaming load, we see that the PSU draws 445W from the wall socket. Again, these are your average results. At ~600W power draw this 1200 Watt PSU should be the the most efficient -- as at 50% load a PSU is usually the most efficient. The efficiency values even slightly below 50% load actually remains roughly at Platinum/Titanium level efficiency albeit offering best in class numbers. It could be a little bit better but with 5 Watt differences we are nitpicking really...