Update 2016-09-13: This entry original said “low-end workstation”, but I don’t think that’s a fair description. The machines I describe here are simply wonderful. They provide insanely great value for money, they are extremely quiet, and because they only need room for two GPUs you can get almost any motherboard and case – it’s not at all as important to get exactly the right hardware as with the quad-GPU machines.
What we’ve done in Stockholm is that pretty much everybody in the team working with image reconstruction has a personal desktop like this. Nobody complains about the noise level (in contrast to the quad-GPU boxes…), and they are literally so cheap that we just get more desktops without thinking much when we need them.
Here, you are not very dependent on specific hardware. In principle you can get any modern machine (including pre-built ones from vendors like Dell, HP, Lenovo, etc.) that is equipped with
- Two unoccupied double-wide PCIe 16x slots (3.0 is better than 2.0)
- A power supply of at least ~500W
However, since we like value for money we’ll get some parts and build a machine that is probably both quieter and more cost-efficient than what you get pre-built. In this case there is a wide variety of hardware you can use, so the links under each item below are mostly examples – and for the same reason I don’t bother showing images of the specific item. You can definitely get even cheaper items, but first we like quality, and second we try to recommend things that are at least similar to what we have used ourselves. These recommendations are current as of early June 2016:
- A good case that is reasonably quiet
We have used e.g. Fractal Design Define R4, currently $79 at Newegg. This case also has external USB3 connectors on the front, which is nice if you need to use external enclosures with micrograph data. - A motherboard with support for dual PCIe 16x slots and Socket 1151 CPUs, e.g. with Z170-A chipset. You can either go for low price ($89 right now) or pick whatever motherboard is best-selling at the time; last time we used the ASUS Z170-A that Newegg has for $155. This motherboard even has USB-C connectors, which will be great for fast data transfer from/to external disks.
- A CPU. We don’t try to save here, but usually buy the fastest 4-core CPU. Currently this is Core i7-6700K for $325. You can get a cheaper one too, but don’t go too cheap since RELION uses a bit of CPU-power.
- 64GB of DDR4 memory, configured as 4 sticks of 16GB each. Brand doesn’t matter, so just pick something cheap from any brand. We found 64GB for $229 at Newegg.
- A power supply. The CPU might use up to 140W, and add 50W for hard drives and other minor stuff. Each NVIDIA GeForce GTX 1070 card will then use max 150W, which brings us to 500W. If you want to GeForce GTX 1080 cards instead you might want to bump this to 600W.
Update 2016-09-13: Over summer, NVIDIA has released the even faster TITAN X Pascal. (Beware: there is also a non-Pascal TITAN X) with 12GB memory that draws up to 250W. Right now you need to buy them directly from NVIDIA, and while the provide the best absolute performance the value-for-money is better with 1080 or 1070 cards. However, if you want to be able to upgrade to TITAN X Pascal, you should get at least a 700W power supply. Newegg has a Corsair CX500 (500W) for $49. - A smaller SSD drive for booting and caching data for RELION. A Samsung 850EVO 256GB is currently $88.
- A larger mechanical hard drive. It’s worth getting a 7200rpm drive for better speed. Newegg has a Toshiba X300 for $140, but any brand will do.
- A quiet CPU fan. Not absolutely necessary, but it will make your office a nicer place at very low cost. The Cooler Master Hyper 212 EVO ($29) is what we usually get, simply because we know it fits in our cases.
- Oh, and you’ll need some GPUs too!
Just get one or two of the “Founder’s Edition” NVIDIA GeForce GTX 1070 from any vendor (this edition is identical between vendors) for $449. Update 2016-10-21: The “Founder’s edition” models are still fine, but by now they have mostly been replaced with vendor models, and can be hard to get. We’ve been quite happy with the even-cheaper ASUS TURBO-GTX1080 ($650) or ASUS TURBO-GTX1070 ($395). However, here we would recommend to be a bit careful! A lot of vendors (including ASUS – avoid their “dual” models) offer overclocked cards that provide even better performance. That can work great when you only put a single card in the machine, but they achieve improved cooling by using bulkier cooling solutions and by blowing the air transversally instead of longitudinally over the card. This can be bad with a multi-GPU config, since you then just rotate air inside the machine of blowing it through the machine (although it might work for a dual-GPU setup if your motherboard allows you to leave some space between the two cards). You can identify these cards with name suffixes such as “OC”, that they have several fans, or by the direction of the fins on the coolers. Do yourself a favor and stay away from all such overclocked cards – it’s not worth worrying about unstable machines to save $50 or maybe getting slightly better performance.
With two GeForce 1070 cards, this machine can be as cheap as $1900, and you can shave off another $100-200 if you go with cheaper components. You will also need a keyboard, mouse, and monitor, but we assume you have that around in the lab.