2Rx8 vs. 2Rx16 RAM Modules

I've recently installed Win Vista and I want to increase my RAM to give the OS some "breathing room".

My current configuration is 2x1GB 2Rx16 PC2-6400s RAM modules.
I want to increase RAM to 3GB by installing a 2GB module in slot "A" and leaving the 1GB module in slot "B".
Don't both modules need to be 2Rx16? Can a 2Rx8 2GB module be used with the 2Rx16 1GB module? What may/will happen if I mix the two types (2Rx8 and 2Rx16)?

 

You should check the manufacturer's specs. The 8 & 16 refer to density. Mix and match; sometimes it works, sometimes it doesn't.

 

MD, your target goal should work. If there's any speed-difference, that might be offset by the larger 'elbow room' that Windows discovers.

You're not going to use the sledgehammer and blow-torch, right? Just checking...

 

No sledge hammer or blow torch.

I just want to give Windows Vista a little more head room. I'm concerned that using two different densities together may not work and I would have wasted the money (I'm on limited fixed income).

 

The concern's understood - shouldn't matter, though - not outside of miliseconds. Take a look at adverts and see how many "6Gb" notebooks are on sale now - a 2Gb and a 4Gb.

 

Mine's a 32-bit computer. Dell says the max RAM it will accommodate is 2GB, but I know for a fact it will support up to 4GB (although I'd only see 3.5GB). I just want matching 2GB and 1GB modules for a total of 3GB — DDR2 PC2-6400s 2Rx16 800MHz (I could use PC2-5300 667MHz because the 800MHz modules I have in it already run at that speed anyway).

I already know that I'd have to pull one of the modules on Windows re-installation

 

I can't find 2Rx16 2GB modules so' I'm just going to get a 4GB (2x2GB) set of the 2Rx8 and leave it at that.