PC Hardware Buyer's Guide September 2010

Folding Rig September 2010

If you're seriously considering building an entire PC just for folding, then you're clearly not going to settle for doing it in a half-baked way. While the recommendations for the awesome folding farm can be applied when choosing hardware for an everyday PC, this system is for maximum ppd per pound per watt.

After discovering what graphics card is best for folding, our folding rig offers the best balance between ppd, cost and energy consumption. If you don't know what folding is all about, it's a distributed computing application that aims to model how proteins fold, thus delivering useful simulation data for scientists to use in the fight against several diseases such as Alzheimer's and Parkinson's disease. The project is run by Stanford University and has made significant progress, as you can read from Folding@home's peer-reviewed research papers.

The genius of f@h is that it's competitive, with a leaderboard and teams. To help us in our quest to be the most productive folders on the planet, join our team by using the team ID of 35947. Cheers!

New This Month

We’ve not seen anything this month that significantly changes our folding farm specification, though it is worth mentioning the amazing EVGA Classified SR-2 oerclockable dual-Xeon motherboard. We managed to pump out 132,000ppd with two 4.37GHz X5680s and four GTX 460s strapped to its ample frame which is an epic amount for a single system. Unfortunately you’d need to sell your kidneys, your firstborn and the unicorn you’re keeping in the garden to afford such a rig, but it’s nice to dream, right?

For those of us who have mortgages to pay, it's good to see a few components have dropped in price, most notably the motherboard. We’ve seen a couple of 768MB GTX 460s for less than the £150 we’ve quoted here too, but they sell out quickly and we couldn’t find any in stock at the time of writing.


We have changed the PSU however, opting for the 1.25KW version of the Revolution 85+ in the UK. This is because the UK market seems suspiciously devoid of the 1.05KW versions, which are a touch cheaper and just as good. If you do spot one, it’s worth snapping it up. The US market still seems to be unaffected by this issue however.

And The Rest

The headline spec in our folding farm is the quartet of 768MB GeForce GTX 460 graphics cards. These are one of the most power-efficient folders at the moment, delivering 56 points per pound and 46 points per watt. Four GTX 460s should generate around 34,500ppd. These figures put even folding stalwarts such as the GeForce 9600 GSO. However, these cards also mean that you need a motherboard with space for four dual-slot graphics cards and a PSU that's got eight 6-pin PCI-E power connectors.

The board we've chosen is the MSI 890FXA-GD70, essentially because it works and it has four dual-slot graphics slots. We've gone with a Socket AM3 board because AMD's cheapest current-generation CPU (the Athlon II X2 240) is much cheaper than Intel's cheapest current-generation CPU (the Pentium G6950). If you wanted to run a few of those massive CPU folding cores, you could opt for an LGA1366 board and Core i7 CPU.


The Athlon II X2 240 processor is sufficient to drive data to all four cards - the CPU doesn't need to do that much in reality, and if you're looking for something slightly lower wattage (remember it won't be at full load, so not reaching the TDP) then you can pay more for a energy efficient Athlon II X2 240e, or simply experiment with undervolting any Socket AM3 CPU.

We've used 2GB of the cheapest branded memory we could find, as there's no gain from fast and expensive memory when folding. In fact, a single stick of 2GB DIMM of 1,333MHz DDR3 is fine (we'd have opted for 1,066MHz, but couldn't find any in stock). To cut power consumption, you might consider using low voltage memory, such as a Kingston LoVo kit or some 1.35V OCZ Low Voltage memory but weigh the extra cost of the kit against the power savings before ordering, and also check that your motherboard allows you to apply low memory voltages.

We've forgone the case too, because we're not confident how any on the market would cope with this many graphics cards long term. In place of a case, we've opted for just a simple solution: one huge fan.

Sit the 200mm Antec Big Boy on top of the graphics cards and it should stop them roasting to an early death.

We've used this setup in our own labs with seven GeForce 9600 GTs in a single Asus X58 WS motherboard and it's worked perfectly and continuously for almost a year now. If you do have a case to recommend us, please let us know.

A cheap 160GB hard drive from a reputable manufacturer will suffice, since not much storage is needed - simply the OS and the small Folding programs are needed. Using an SSD won't cut much from your power bill, so don't bother with one.

Finally, drop on the same Akasa AK-876 or Arctic Cooling Freezer 64 Pro that we also used in the Affordable All Rounder PC for ample cooling. If you want to save a few quid, the reference AMD cooler will suffice.