Here's the stock bios from my sapphire - http://halo112358.googlepages.com/bios.rom

I'm pretty sure that using RBE to tweak the fan settings is what caused the card to not post on a cold boot. Funny that it worked fine for a day until I shut the machine off and back on (totally explainable). Should I track down an old PCI video card and use it to boot up and flash the stock bios back onto the board?

If I can get the card working again I'll cancel the RMA and order a crossfire motherboard - I already have another 4870 on the way