HD 6990 Bitcoin mining

When building a Bitcoin mining rig the thing you have to keep in mind is the whole thing is more or less a life support system for the graphics card that you’re going to put into it.

• Properly configured, a Bitcoin mining rig uses little CPU but pushes the graphics card (where all of the fancy Bitcoin math happens) to the limit!

• You must use an ATI graphics card! Other cards, such as nVidia lack the GPU instructions Bitcoin requires.

• You must ensure that you motherboard has one or more PCIE 16x slots.

• You can really skimp on CPU power and hard disk space.

• A heavy-duty power supply in the 1000W range is a must, without it your graphics card won’t work!

• System memory (RAM) can be modest but should not be below 2GB in most cases.

Selecting a Motherboard

Lets start with the motherboard. I was extremely tempted to find a dual or triple PCIe 16x motherboard. However, most of these boards are quite expensive at the time of this writing. So, I went with the Zotac GeForce 6100 Micro-ATX AMD Motherboard GF6100-F-E which has only 1 PCIe 16x slot. It should prove to be an excellent and inexpensive basis for our Bitcoin mining rig. I selected this model for a number of reasons:

Price. It’s an extremely inexpensive board.
Capability. This board has an AM2/AM3 socket. This means that you can put an old single-core AMD Sempron into it for less than $40 dollars. This is great, because while Bitcoin mining rigs beat the tar out of their graphics card’s GPU they don’t really stress the CPU much at all. If, however, you’re using this system for a Bitcoin mining rig and something else (like a file server) at the same time, do get a stronger CPU.

Selecting a CPU

Unlike nearly every other scenario this is one of those rare times where the processor’s speed does not mean much at all. Nearly all of the heavy lifting happens in the GPU, not the processor. So, if you want to save money on this build, select the least expensive processor and move on. That’s what I’ve done here. I selected the AMD Sempron 145 Processor for the budget Bitcoin mining rig build. It’s fast enough for the needs of the system and it’s really inexpensive. My only complaint is I could not find a socket compatible 64bit processor for the same price and availability. Oh, well, you can’t have everything I guess.