I recently built a machine with the following configuration :-
CPU - i7 930
RAM - 2GB * 3 = 6GB, DDR3, 1333 MHz by Corsair
Motherboard - Gigabyte GA-x58A-UD3R
Graphics card - ATI Radeaon HD4550
Power supply - 550 W
OS - Ubuntu 10.10
Everything works well except the total RAM detected by the BIOS. Sometimes during startup, the BIOS detects the full 6 GB of Ram and sometimes it detects only 4 GB. Any idea, why this could be happening? Any help in this regard is greatly appreciated.