well, it seems like you have a few things backwards. your current system is a gt 620 with a core 2 quad... I would pair the gtx460 with the core 2 quad and put the gt 620 with the i7 3770k. the gt 620 is not that great of a video card to be honest, its ddr3 (instead of ddr5) and it has less cores than the 3770k's onboard graphics. if you are worried about power supply, a gtx 460 requires a PSU with 450 watts. also, is the 3770k system already built? or are you looking to just pop a 3770k into your current system? if that's the case, you cannot do that. the Core 2 Quad and I7 3770K are two different motherboard sockets entirely.