i have a 4 and 1/2 year old PC that i mostly use for gaming, but since i havn't upgraded it since i got it, you can imagine that doesn't work so well any more. i'm looking to buy a new graphics card, specifically the MSI GeForce 6600 (http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1240060&CatId=935)to replace my aging GForce4 MX 420. the problem is, my MX has an AGI 4x bus, and the GeForce 6600 has a 8x bus. i'm not very experience when it comes to doing this kinda stuff, so will they be compatible, will i need to get some kinda driver, or will i need to get a new bus or something?