Vista Service Pack 1?
1 May 08
My friend has a similar problem, he has 2x2G(not dual channel type) plus 1GB and instead of 5 vista reported only 3. What he did was install the 64bit vista version with out the SP1, and it works. He is now enjoying all 5 GB RAM.
30 Apr 08
just as I thought, I just had that idea because i read somewhere that after installing sp1, 4g of ram showed in 32bit version, and as i suspected, it is just a false claim, was planning to upgrade to 4g ram but i think that there's no sense in doing so since my system can't fully utilize it. and for now 2g of ram running in dual channel mode is sufficient enough to handle anything that i can throw at it.