How much memory can XP use?

[ImaNihilist]

After 2GB, Windows XP doesn't seem to really manage the extra RAM very well. You can go up to 3GB, but you can't actually go up to 4GB as I understand it because some memory addressing space is used up by other things, such as the video card memory. So if you have a 512MB video card, you can't really go higher than 3.5GB of system RAM.

I suppose you can go up to 3GB if you really want, but more than that isn't worth it. I guess if you really want to max out Windows XP the best way to do it would be use two 1GB DIMMs and two 512MB DIMMs. I'd say that's the absolute maximum you'd really want to go up to in XP. You also might have trouble doing that with an AMD based system, because they can be kind of picky about populating all four DIMMs and using different size/latency memory.