What are the advantages of having a 4gb card over a 2 gb? I currently have 2 gigabyte gtx 680s that have 2gb. I recently purchased another system that has an EVGA 4gb card, i dont know weather or not to sell the 2 2gb cards and get another 4 gb card; or sell the 4gb card and keep my 2 2gb cards and save a few bucks. Any help would be greatly appreciated.