I think my power supply is not good enough to handle sapphire hd 7770 ghz oc. so i want to buy sapphire hd 7750. now i want to know what is the performance of hd 7750 . is it really poor than hd 7770 oc? (my power supply is tr2 420)
it should run just fine. a lot of those PSU recommendations from graphics cards are based on assumptions of X amount of power for CPU, and X amount of power for hard drives, and X amount of extra space "just in case"
oh, you've got more than enough power available to run a 7770 card. even if you were to try to overclock you might be ok. you might even be able to go to a 7790 if you want (but the card will obviously cost you more).