Speccy

I have a system with 6GB Memory that is 800MHz DDR2 2048 MB

Speccy is right on all counts except it says it's 400MHz.

DDR2-800 Dual Channel ram is 400Mhz per channel so its really 400Mhz x2,

Unless you have DDR2-1600 Ram...

Try another System Tool (like http://www.cpuid.com/ ) and the ram settings your BIOS to compare.