I have a server I've installed Windows Web 2008 R2 on, which is reporting that I have double the physical memory installed as is actually the case. In msinfo32 "Installed Physical Memory" shows as 2x what ever the actual installed amount is, though "Total Physical Memory" shows the correct amount. The "System" info window shows installed memory as 2x, with the correct amount in parenthesis listed as the "usable" amount).

This server mistakenly had Windows Web 2008 (32-bit) installed on it just previously, and that OS also reported the same faulty information as Win2K8R2 is reporting.

BIOS reports the correct amount, memtest was run on this server before installation, and a previous Windows 2000 instance installed on this system also reported the correct amount, as I recall. Server operation seems to be fine as well (it's only trying to use the correct amount of memory).

The server is a generic pizzabox running on a SuperMicro X6DVL-EG with dual Xeon-3.2's. Memory installed are 4 matching mt18vddf12872g-335c3 sticks (1GB pc2700 DDR ECC REG cl2.5) This behavior occurs whether two or all four are installed.

So, has anyone seen something like this before? Have any idea about what's causing it, and how I should be concerned about it? Everything else seems good so far, and I'll be upgrading the memory before putting the server into service, but I don't want to spend too much time/money/effort on the server if it's got something odd going wrong here.

UPDATE: There was a question I ran into regarding memory sparing in the BIOS and a possible (buggy) effect thereof; however, flipping that bit back and forth in the BIOS revealed that isn't the issue.

Still flummoxed a bit about this one, though I still have seen no negative impacts.

Post-Answer Update (January 13, 2011): Upgrading the system with new, larger memory has fixed this issue.