512 or 768 memory upgrade

Hi all,

2 weeks ago I got a 4550 with 256 Megs of 2700 Ram

I was reading that windows XP works best with 512 Megs, so I thought I would upgrade my memory to 512.

Would it be better to go aheqad and get a 512 Stick and have 768 instead of 512, would there be any real difference?

I do play some 3D heavy games like NeverWinter Nights and Unreal 2003 and use Paintshop Pro, Poser and Bryce, all of these seem to work fine with 256 Megs, thats what i had on my other computer before I bought this one and it was only a P3 600, so things run better now then they were, but was wondering if there was a reason to go ahead and spend the extra 30 dollars for 512 instead of 256 Megs, or if it would be a wast of cash for not that much more of a improvement..

Thanks in Advance.