Can I use 2 different size RAM ?

[CW1]

Currently have a single 512MB RAM in a Compaq Presario and want to add 2GB. There's 4 slots, so can I just add 2 x 1GB and have a total of 2.512GB or would I need to remove the 512MB ?
Same for a Packard Bell (when I find out which RAM to buy !)
http://www.theanswerbank.co.uk/Technology/Question805342.html
There's 2 slots, one has 512MB. can I just add a 2GB RAM ?

[ChuckFickens]

I assume ones a desktop, as you've not given any details as to what desktop over than a make it's hard to say, chances are it will work, but if not just remove the 512Mb so you have 2gb, that's enough for most people.

for the laptop just add another DDR2-533Mhz SODIMM and it will work fine.

[CW1]

They're both desktops ;o)

[Hymie]

I don’t see why a computer would be upset by differing RAM volumes in available slots.

I have 128MB + 256MB in my PC, when adding the 256MB, I never considered that the different RAM size would be a problem.

[CW1]

Hi Hymie,
Didn't have a problem with an old desktop but when I've been searching for RAM, I came across this 'Dual Channel" thing where, as I understand it (and I don't always !) the same RAM has to be installed in corresponding slots. I don't know if that applies to mine. "Suck it 'n see", I guess !

[Hymie]

Besides the time and effort you have spent checking out the type/size/manufacturer of RAM you want to add to your PC – I trust you have identified that the RAM you have is limiting the performance of your PC.

Once you have sufficient RAM for your most demanding application, adding further RAM will not improve your PC’s performance – but could have a detrimental effect on your bank balance.

[fo3nix]

You must use the same type of RAM (ideally the same speeds too), but the capacities of the different sticks doesn't matter.

A 512MB stick can be combined with a 1GB stick, as long as their types match.

It's better, though (there may be a slight speed improvement), if the two sticks are the same size, i.e., 2x512MB sticks, or 2x1GB sticks, etc. (assuming you have two RAM slots).