I am proud to introduce the PC that was once a time-killing machine that I transformed into to the most productive thing I own. How? By devoting its resources toward scientific and medical research, all while warming up my apartment in the cold months. It’s easy to sleep at night knowing my place is warmed up via a machine that cures cancer! The primary application of this PC is BOINC, which utilizes all of the available resources of the PC for various scientific research projects.
Back in 2011 when most of the parts were new, this PC would have been worth over $3000. By the 2017 standards, this is a bit outdated, though still no slouch:
- Gigabyte GA-890FXA-UD5 rev 2.0 with F7e BIOS
- AMD FX-6300, overclocked to 4.4GHz (was at 4.7 but the transistors degraded)
- 4GB of DDR3 RAM, at 1600MHz
- Apeva 700W PSU
- Western Digital 40GB 5400RPM ATA hard drive
- Abit 802.11g PCIe Wifi
- AMD V7900 (in a x8 slot)
- AMD V4900 (in a x4 slot)
- AMD HD 7770 (in a x8 slot)
- PCI diagnostic card (to check voltage levels and if the PC has crashed)
- A home-made liquid cooling system (more on that later)
I have one spare x16 lot to use, which I intend to put my current R9 290 into when I retire it from gaming. I have an Nvidia Quadro 4000 that I was planning on setting up, but doing so adds a lot more complexity without enough of a gain; I’d rather built a separate Nvidia-centric system.
The platform was built upon a piece of particleboard that came from my desk, and I used any random pieces I had lying around to brace everything together. The hard drive may be terrible but it is plenty large and fast enough for the needs of this PC – Linux, video drivers, BOINC, and BOINC data are pretty much all that is installed on this. The wifi is really only needed to run updates, get more data to crunch, and to run SSH. So, no need for anything fancy and new.
As of writing, the wattage seems to peak at roughly 600W under full load, but on average it is more like 530W. If I do just CPU calculations, the wattage drops to around 325W. The GPUs collectively consume about 60W when idle.
Hardware temperatures are decent, considering how cramped everything is. The CPU doesn’t seem to get much higher than 55C, while the V7900 peaks at around 70C with the stock fan profile. The cooler these parts run, the better, since that means their heat is dumped into the room!
One of my concerns with this PC was how much power was being drawn from the motherboard to power the GPUs, especially since the V4900 has no external power connector at all. I figured to help alleviate this problem, I would use a PCIe riser cable with a 12v Molex connector. There were no diodes, so the power should run back through the motherboard. I attached the WiFi card to the other end of it.
At the “front” of the PC you may have noticed a blue LCD, which is the water temperature in the “reservoir”. This number seems to remain in the low 30s, even when running the system under full load for hours. The reservoir is just a glass food jar that happened to fit the water pump. I bought both the LCD thermometer and the water pump on eBay for about $12 total. The jar was basically free.
As for the rest of the liquid cooling system, that gets a little more interesting. A while ago I bought this massive Zalman heatsink, that was too big to fit in the PC I intended to install it in. At the time, I was unaware that “heat pipes” are literally pipes with vapors stored under negative pressure; I thought they were just solid copper rods. I cut the tips off the pipes in order to save space, only to find the heatsink was effectively useless. But, just because of my ignorant mistake, I wasn’t about to let go of what was otherwise a nice product!
I bought some tubing, with a 5mm inner diameter. The inner diameter fit snugly with the tips of the heatpipes, and the outer diameter was roughly the same as the water pump’s. I connected one tube to the water pump via 8mm heat-shrink tubing. Everything else was ziptied, to ensure the tubes would not pop loose. Since I cut the heatpipes so short, I needed to remove 3 layers of the aluminum fins. You can see where Zalman went cheap, and only nickel-plated the visible part of the heatsink.
Overall, I spent roughly $50 on this liquid cooling system, and it met my expectations. The fans are a bit loud, but the water pump is quiet anyway. In the perspective of the image above, the water flows from the front of the heatsink and flows toward the back. The front of heatsinks tend to remain the hottest (because that’s where all the heat reaches last), so I figured it made sense to have the cold water start from the hottest point and exit from the coolest, where it should help balance the temperature. Doing this would likely increase the minimum temperature, but lower the maximum temperature. The maximum temperature is my main concern, as this is meant to run 24/7.
Several sources in my research will tell you that the amount of heat per watt a computer would output is roughly equal to the that of a radiator. In other words, if I had an electric radiator operate at 600W, it would output roughly the same amount of heat as this PC. Therefore, I call this the “Productive Radiator” because it isn’t just using up electricity to keep me warm – it’s using electricity to perform research, while keeping me warm as a side effect.