As the title says I need to know what kind of RAM to buy for an ECS PF21 Extreme mobo, i currently have a wintec AMPX 1 stick of 512 mb of ram in it, however i want to upgrade to 2 gigs, and since i can not find the AMPX stick of RAM i had bought on newegg again im just gonna go and get 2 1 gig RAM stick but i have no idea what to buy. All i know from heart is that its a 240 pin connector, ddr2, and i think its pc2 - 4200 (I have no idea what PC2 - 4200 means). But yeah that's about it. I would prefer the RAM to have a heatsink that comes with it. I was thinking about getting this http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1882393&CatId=2366 . Is this the right thing to get? Any suggestions? I'd prefer the price to be around $50.