I would say (from experience) to not get a board that needs a BIOS flash for that CPU, cause (in my cause) you need an older CPU as well to flash the BIOS with. If you want to use that 5770 as only one card, look at some Gigabyte boards with 790FX and 790X chipsets. But if you want ASUS use a M4A78 Pro for one 5770. If you want to Xfire (i highly recommend) i would say M4A79 Deluxe.
FYI. my old board was an XFX 750a SLI board, and it never ran well with this CPU. But this supported PHII from the factory and i've nevr had an issue with it
EDIT: welcome to the forums!
FYI. my old board was an XFX 750a SLI board, and it never ran well with this CPU. But this supported PHII from the factory and i've nevr had an issue with it
EDIT: welcome to the forums!