After building a new computer with this board it wouldn't recognize either a XFX HD5870 or the R7780 plugged into the PCI-E x16 expansion slot. When I did manage to get the enter BIOS screen displayed by unplugging the PCI-E card completelyand connecting the onboard HDMI to a 1080p display it appeared that the PCI-E GPU's were not being seen addressed during post.
After several re-slots without a video cable connected to the PCI-E GPU, so I could see what was going on in the BIOS on the 1080p connected to the onboard HDMI, I did eventually manage to get the 5870 to be recognized in the BIOS and have an address space allocatted after which it worked ok using the DVI to a Dell 24" Ultra sharp 1900x1200 and the GPU cards HDMI to a 1080p screen. It was hit and miss though for the BIOS to recognise the card immediately (managed to get it recognized 2 times after which gave up since it was working) after starting fresh and re-slotting the card each time and entering BIOS to see if an address was allocated. The 7870 was just never recognized and addressed ever.
After updating the BIOS, to v.590, the 5870 seems to be automatically recognized (not extensively verified) and given an address all the time however the 7870 still will just never be recognized and given an address in the BIOS even after numerous re-slots. I recently flashed to v.60 BIOS and will try again this weekend to see if the 7870 can ever be automatically recognized by the BIOS and addressed.
Anyone know if this is a problem with the BIOS and might be fixed in a future flash? It seems to me to be a BIOS problem where the PCI-E GPU's are not being seen during post and allocated an address and as such are non-existent. Anyone know of a soultion to this problem? I tried many different BIOS configurations during all this. The 5870 appears now to be recognized all the time on default BIOS setting for the video in the latest BIOS version (requires more testing to verify) but the 7870 still refuses to be seen by the BIOS at least on the v.59.