Hi, i want to buy a graphics card to play 1080p and improve play back of 720p mkv HD video files, the two graphics cards i have chosen are: ATI Radeon HD 3450 PCI Express 2.0 512MB DDR2 64-Bit and the Asus ATI Radeon HD 3650 Vcool Silent 512MB GDDR3 Would the more expensive HD 3650 be better or would the 3450 do the job just as well for video play back, my computer plays 720p smoothly but struggles with some 1080p files, thanks for any input.