An old chestnut but here goes: My mobo supports 4Gb of RAM in 4 slots. Until this morning I had 2Gb fitted (matched pair of 1Gb in slots 1 and 3 and dual channel). Safe in the knowledge XP Home will support 3Gb of RAM, I fitted another matched pair (2 x 512Mb) in slots 2 and 4, still dual channel and maxed to 3Gb. Problem: the OS only recognizes the original 2Gb? Set-up tells me 3Gb is fitted by only 2Gb is usable?? (this note is grayed out). I have googled and found many people have fitted 4Gb and found only 3Gb recognized but nothing to suit my case of 3Gb fitted and only 2Gb recognized! Anyone please and thanks in advance as usual.
Thanks for the link Marv. I was there before but it left my brain a bit numb... I haven't tried swapping around yet MAT as I thought I would try to resolve the issue first. The additional memory has been recognized in the BIOS set-up where it simply states "3Gb of memory fitted, 2Gb usable". I suspect swapping it around will only produce the same thing.
The maximum memory available in 32-bit versions of Windows Vista is typically 3.12 GB. is what the Microsoft website says plus you can add on whatever a shared graphics memory might need. So to make the most of Vista 32bit you need to install 4Gb.
No, not the same type. I was under the impression the individual "pairs" don't have to be the same type, just each single module within a pair. Not certain about the latest BIOS so I'll give that a check. The mobo is ASUS A8N-SLI. What miffs me is I have read numerous articles about upgrades going up from 2-4Gb and only getting 3Gb recognised! :-(
A dual channel memory system typically has either two or four memory sockets, and each socket belongs to one channel or the other, and it matters, also, not only what you install but in which sockets you install it. So you can have a set of four memory modules (two pairs of two different sizes, for example ... say two 512MB modules and two 256MB modules) that would work properly in the system in all regards, yet if you simply install those 4 modules into the wrong sockets the system may not run at all, or may run with the memory system speed cut by half.
Asus can be fussy about memory, I have bought perfectly good and supposedly compatible memory sticks which didn't work - although they were fine in another machine. Suggest you use the Crucial tool to check your motherboard and recommend a guaranteed memory match.