A GTX 640 is far from being a super power card, it is a fair bit weaker than the card I got with my Phenom II 940 back when it was fairly new... So, your Phenom II 965 will have more than enough power for such a card. Now, is that a good price or are you better off buying a card used... I would probably opt for the 2nd option, but that depends on what u wanna do.
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