Well buying a Graphics card considering VGA memory should not be one's buying criteria ! One should look at the inbuilt IMC {Integrated Memory Controller} which helps in transferring data. Lets say a 256bit GPU will work good in 256 , 320 but will even work nice on 512 VGA but a GPU with 256bit IMC and 1Gb Memory will not perform better than 512 variant .. So better buy a card seeing IMC rather with double ram or same Never buy too pumped cad like 8800GT with 1Gb memory