Head2Head: Power Supplies

How we tested: Big Willy
If you want a load that reacts like a computer and can sink a massive amount of juice, the best option is to build a massive computer.

Say hello to Big Willy.


It's half nutcase gaming rig, half storage server and all insanity. We joke that it uses 0.486 rainforests per day whenever anyone in the office mentions green computing.

We're using an ASUS board based on the X48 chipset, which gives us two PCI-e 16x lanes and a PCI-e 1x lane to play with, as well as eight SATA ports. And we're happy to report that we managed to max them, as well as the rest of the board, completely out.

We started with an Intel quad core QX6850, the fastest quad core that was manufactured on the 65nm process. We chose this in the name of energy inefficiency. We aimed Stress Prime at two of the cores to saturate them with work, leaving the other two there for other tasks. Stress Prime uses fast Fourier transformations to calculate positive prime integers that are one less than a power of two, and decimates processors in its wake.

In the 16x sockets are two ATI Radeon 4870X2s. These cards contain two of the highest end graphics cores available on one PCB, as well as a hardware Crossfire bridge that makes them appear as one card. Initially we had planned to run Folding@home on all four cores, however the GPU folding client has to address the GPUs individually, and the hardware Crossfire bridge prevents this. If you run it, you see 50 per cent usage on the card, and if you probe GPUs, you can see one processor working at 100 per cent and the other at zero.

We decided to use 3DMark Vantage instead, because it scales quite well across four GPUs and makes the cards sweat like they should. We ran a few loops of ‘New Calico’, its second GPU test, with every setting at extreme, and the resolution at 2,560 x 1,600 – the maximum we could pump into a 30in Dell monitor. We saw all the GPU cores running at between 70 and 85 per cent during the test. So far the four cores on the CPU run at about 70 per cent between them. But there’s more.

In the board’s last remaining PCI-e slot is an Adaptec 31605 SAS card. It can talk to both SATA and Serially Attached SCSI drives. It can connect directly to 16 hard drives or, with extra hardware, 128. It has its own processor that gets damn hot. It belongs in a server. Attached to this are 16 Western Digital 500GB hard drives divided into four RAID5 setups. There are another eight connected to the motherboard, taking Big Willy’s total to 24. But what to do with them all?

We ran IOMeter in the background, which thrashes the hard drives by queuing commands for them to complete. And it feels good to do that on four different RAID5 setups simultaneously.

There’s 4GB of DDR3 in there, too. We tried to build a bigger computer. We really did. But we ran out of I/O.

So we plugged in 14 fans. Nine for the hard drives, one for the SAS card, three for the GPUs and one on the CPU’s heatsink.

Big Willy, without the power supply, would retail for – wait for it – over $9000(!).

Don’t even try to act like you don’t want one.