You probably won't really notice the difference in the video cards. Instead of the extra RAM you may want to buy a second hard drive specifically as a working drive in order to keep programs and things off of interfering with transfer speeds while working on videos. Possibly even a RAID0 of 2 smaller drives if you work with uncompressed video at all. Keep in mind that 1920x1080 is 2073600 pixels . . . at three bytes per pixel that is 6MiB per frame . . . at 29.94FPS that's 186MiB/s.