The GTX 460 1GB is only one tier above the GTX 275, probably about a 10% performance boost over your current card. At 1680x1050 I doubt you would see a worthwhile performance difference over your current card. Unless you really want the DX11 support that the 460 has it really isn't worthwhile upgrading. You're probably better off saving the money for a more powerful card and/or a higher resolution monitor.