Yes with BIOS updates (if needed) should work. As I tell you if you are planning to get CX600 go get it. It'll be good for you and have good upgradebility. Is it 6770 or 6670? If I'm not wrong you said 6670 before. Both 6670 or 6770 will do in your 450W (If it's lower than 24A on the +12V Rail No for 6770 sorry, but mostly 450W will have above 24A). But if you are going to get CX600, it is not wrong idea. Go get it.
no man he said hd 6770 in his previous thread.