http://ubuntuforums.org – Hello- I have just removed 2 x 1GB DDR2 DIMMS from my desktop and replaced then with 2 x 2GB DDR2 DIMMS. On boot the Bios reports only 3GB is usuable - this is before the OS boots. There are two OS's, 64 bit Ubuntu and 32 bit XP. Both report 3GB of available RAM. (Hardware)