What ram and how much 9300????

Hello brought a dell 9300 from dell.uk great laptop but i only went for a 512mb option but games like wow and battlefield 2 are laggy im guessing this is due to the ram. Does anyone know what ram i need and how much i can and should buy?

Ive found these are they right? 1 x 512mb 533mhz http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=174827

1 x 1024mb 533mhz
http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=217961

Anyone know how much i need 2gig or ram or is 1024 enough? I have the 6800go cards and love gaming.

Also any cheaper links would be great if there are any.

Also i currently have 2 x 256mb in there can i buy a single 1024mb and also still use one of the 256mb's?

1024mb should be enough, open up your dimm area (marked m) and see if they gave you 1x512mb or 2x256mb. if 1, try and get one identical to it (chip wise at least), if 2x256mb, you'll need to order 2x512mb. make sure to get high speed +3200, and something with a latency of 2.5 for best operation, but since it's DDR2 you might have to settle for CAS3.

Not ture. I ordered my Dell with just 256 and I added a 1GB stick for 1.25. Look for any decent brand of DDR2 533, like Crucial Kingston, corsair ect... and it will work just fine.