Need advice on a memory upgrade

[Semnae]

I don't really know anything about computer hardware at all, and I've been rather overwhelmed these past few days with all these unfamiliar words like unbuffered, ecc, and cas latency. All I know is that when I enter Ironforge in World of Warcraft my computer lags like crazy while it loads the characters of all the players gathered there, and I want that lag to stop. I am currently running a total of 512Mb of Dual Channel memory, and as I understand it, this is the cause of my game lag. My brother tells me that Patriot Memory is the best, so I'm asking here for advice. What would you recomend I buy?

Here are my system specs for my desktop pc:
Motherboard - Biostar M7NCD Pro (http://www.biostar-usa.com/mbdetails.asp?model=M7NCD%20PRO)
CPU - AMD Athlon XP 2800+ (Barton)

[IcyTroll]

the patriot part number that you can use can either be the psd2g400k or you can get 2 psd1g333. you can get the pc3200 memory now so you dont ahve to upgrade later when you upgrade you cup. you can also get the 2 pc2700 memory so it really up to you. you may lag also do to the fact of your vga card could be a bit slow.