Simple RAM question.

[Alwightmush]

Hopefully just a quick and simple one.
My brother is looking to add some more RAM to his machine.
He has 4 slots, 2 available with the other 2 occupied with Corsair 2GB (2x1GB) DDR2 800MHz/PC2 6400 PC RAM currently.
He is also using 32bit Windows 7.

If he were to add some more RAM what would be his options?
I understand that using 32bit Windows he will only be able to use somewhere in the region of 3.5 Gb of RAM?
Would it be possible to add a single 1Gb stick of the same memory to one of the 2 open slots?

His processor is a Q6600 and graphics card I think is a 9800gtx or thereabouts. So his machine is getting on a bit but I think he would just like a slight boost when dealing with multiple programs.

Thanks in advance.

 

[Surveyor]

Whatever you add will need to match the existing RAM in terms of speed, timings and voltage.

You could add a single 1GB stick but that would mess up the dual channel operation and you'd end up with a pair operating in dual channel mode plus the third stick in single channel mode or possibly all three sticks would end up operating in single channel mode.

Adding another 2x1GB sticks would be the best option even if you can't use it all.

 

[lollyhayes]

You may as well add another 2x1gb for two reasons: he may decide to go 64bit in the future, and also the price of a 1gb and 2x1gb sticks are virtually the same...