Again, I can’t say I know much about the X58 mobos, but I have read that the Intel version is the “simplest”, and also the most stable. I have ASUS mobos in all my PCs and they are great, but, they have a lot of extra “bells and whistles”, mostly for gamers who like to overclock their machines.
But getting back to your question. I answered a similar post in a different thread. Does the BIOS have a setting for “Memory Hole” or “Memory Remapping”? Each hardware device uses memory addresses, which Windows assigns in the 3GB to 4GB range. On my Vista x64 PC, the Intensity Pro uses two small pieces of memory, roughly at the 3.7GB address location.
Normally, the use of the 3-4GB address space for devices doesn’t pose a problem, as long as you have < 3GB of RAM. The BIOS remapping options map the 3-4GB memory space to above 4GB. I doubt that this is your problem but you never know.