If I added more RAM...

to this computer:
AMD XP 2000+ Processor
80GB HD
256MB PC2100 RAM
Integrated Graphics
Windows XP

Will I see a significant performance increase in Windows? Say I raise it to 512? 768? 1GB?

I'd say stick in a Gigabyte. You should see quite an improvement to Windows, but games-wise, if it runs now, it' will run better. If it doesn't - don't hold your breath.

You will see an improvement but it probably won't be as much as you would like. I agree with Snograt. Go for a Gig but if you are looking for an improvement in games invest some money in a graphics card.

Ram 1gb then shouldnt be expensive get some more memory and Graphics card would make it even more better. but yeah 1gt

My advice: go to Crucial and use their system scanner. http://www.crucial.com/systemscanner/index.aspx - just click the "Begin scan" button.

This will show you what memory types and configurations your system can support and will then try to sell you some. Crucial have competetive prices and a good range of brands, so that's probably all you need to do.

As others have said, a graphics card would help too. Probably AGP judging by your specs - almost any would be better than integrated graphics.

Be careful, though. Add up the price of the memory and a graphics card and you may well see the advantages of a brand new, moderately priced PC

256 Meg is not a lot of memory for XP, so you would see a significant performance increase even going to just 512MB. How much RAM you could add, and what it would cost depends somewhat upon what you have now (how many slots are used) and how many slots you have.

The extra RAM would increase the performance of WinXP and apps, but as has been said, you're never going to get great performance in games with that cpu and integrated graphics.

the more ram you have the faster your pc will work

I can't see how your PC can actually run at the moment with just XP, 256MB and integrated/shared graphics. It must use the swap file more than it uses anything else.

Upgrade man, everything is so cheap atm, you would only need to spend £100-200 to get it running pretty decent, thats if you know what you're buying

You won't need more than 1GB on that machine 256MB is just too little.
2 Sticks of 512 MB @ PC3200 would be ideal.

ty guys this is a friend's computer, and I wanted to make sure that he would see an actual increase in performance before spending $50 on RAM. He's got 2 slots total, so I'll just buy 2 512 sticks.

Just make sure you buy the right ones.

There is 184 pin and 240 pin.. and such, have to read the Motherboard's manual and find out what type is compatible.

Like I said - use the Crucial scanner, it won't sell you the wrong type

He's currently using PC2100, so it's obviously 184-pins!
So ask for PC3200 (DDR400). It's backwards compatible in case your board only supports PC2100 (DDR266).

I don't like Crucial scanner, it's not that it's bad, just that it's unnecessary to install. But that's my 2cents.

Bah, what's a little ActiveX between friends?

Heh, I sound like I work for Crucial the way I advertise that thing. It's just that I'm not the techiest person on earth (as you lot well know) and the scanner makes memory upgrades error-free. It's a great marketing tool for them as well - tells you what you need, then sells it to you.

Now, if there was a similar one that did a whole mobo scan and could tell you what memory/processor/gpu you could fit, this tech forum would shrink considerably!

I found this was great and use it all the time CPU-Z

True - cpu-z is a very nice little app.

For total technophobes, however, I stand by my suggestion

256mb to 1gb will greatly reduce the loading time in populated districts.

but wouldnt the graphic card be its bottle neck?

Yes, but it's still going to be a significant improvement.

This is budget upgrading we're talking