My 4 x 7950 (Sapphire Dual-X OC) mining rig with a Gigabyte GA-970A-DS3 mobo, 2x650W Cooler Master PSUs and high-power wireless usb adapter (only cause I leave it down in the garage where it's cooler and wi-fi is weak). Does around 2500 kh/s for LTC with cgminer on xubuntu. Boots of USB, no hard drive. The crate was just a plastic crate some restaurant was throwing away. Everything is held together with zip-ties