Need Some Help

I am having some issues with a P55 motherboard this morning that I want to reach out to our community about and see if you guys have any ideas what is afoot here.

The problem is this. I have installed 4GB of RAM (2x2GB), but the OS only sees "1.99 GB Usable." I have used both Core i5 and Core i7 processors in this ASUS Maximus III Gene motherboard as well as confirmed this issue with Corsair, Patriot, and OCZ memory modules. The problem however is not static. It has "gone away" once when changing out the processor, but then returned when switching out RAM modules. The original thought was that the DIMMs were not seating well, but I have gone as far to put a 5lbs. weight on top of the DIMMs. I am using an v7600 Windows 7 64-bit OS. I have tried turning off Superfetch services as well as disabling remapping the memory in the BIOS.

As you can see in the screenshot above, 1.99 GB is marked as usable and the Task Manager verifies that total usable. Trying to force more will "lock up" an application. But do notice that CPUZ does see the full 4GB. When the system POSTs however, it only shows as having "2048MB" installed.

I have found one more instance of this on THG forums using a GIGABYTE P55-UD4 motherboard so it does not seem to be an ASUS-only issue. If you have any ideas, please sound off in this HardForum thread. Hopefully I am just overlooking something simple.