Tying to sort out the memory hole issue with 4G of RAM. When the BIOS posts, it shows up about 512M short of how much physical RAM is in the box. With the MMIO option disabled (default setting) the machine will post, but WinXP-64 reports back the total RAM is the same as the BIOS. Enabling the MMIO option (which remaps the memory around the 32-bit PCI devices) causes the board not to post at all. Popped my RAM into another brand of motherboard and it was golden. Memtested each stick, in pairs, and all four sticks without issues either. Trying to sort out if this is a bug in my board or if it hits DFI owners. Anyone else out there running 4G of RAM with MMIO enabled?