Graphic card for high definition video editing?

I am thinking of getting a new computer and want to edit high definition video on it and I wondering about graphic cards,



My chief aim is to edit high definition video, but I would also like to hook up a second monitor to the computer as well and thirdly wouldn't mind playing a game or two on it,



the computer I am planning on getting will be a desktop with 4 gigs of ram. how much ram should my graphic card have?



thanks|||Get one with 512 megabytes or more.|||Hi. For Hi-Def editing you will want the fastest, most intensive memory card you can find. Some are quite expensive.