I have Dell Preceision 690 with 2gb RAM. I bought additonal 1gbX2 ram from Dell which are supposed to be compatible to this machine. When I install new RAM, system shows total of only 3gb instead of 4gb ram. In Bios set up also installed memory is shown as 3gb where as in BIOS, under size column I am able to see new RAMs as Rank 2.
Any suggestions what could possibly wrong here?


does bios show all 4 gigs of ram?

On bios screen, on the top line Installed Memory is shown as 3gb and under tabular view, Size column lists 4gb including new 2 1gbs.

Sounds like a memory hole problem. Check BIOS settings. I would call Dell Customer Support and ask them because it's different on every motherboard.

I talked to Dell and they could not suggest anything on this part. so I thought I could check on this forum.

Windows XP will not show more than 3.something gigs of ram due to architecture limitations.
You need to use Vista or *nix/BSD for true support of 4Gb although I believe there is a reg tweak to allow XP to see all 4 gig.

windows server (but not so much datacenter and enterprise) also have issues adressing large amounts of ram