MSI 890FXA-GD70 890FX Socket AM3 8 Channel HD Audio Gigabit Lan ATX Motherboard
XFX 850W Power Supply
AMD Sempron 140 2.70GHz (Socket AM3) Processor
Corsair Value 2GB (1x2GB) DDR3 PC3-10666C9 1333MHz

I'll experiment with 1 card and see how it goes.

I'm assuming I should be getting 800+ MH/s out of these two together. Is that correct?

My solo 5870 is pulling 410+ on a really old system.

Btw, their not crossfired. Is it worth me crossfiring them?