gt610, unfortunately, it is THE slowest among the 600 series. You're clue is this (as long as they stick to the naming scheme),
the lower the model number, the slower it is. for 600 series we have 610 up to 680 (with 690 having dual), 650 is about middle of the pack.
in short, it's not even a gaming card. so for 700 series, don't buy 710, 750Ti is a good place to start, you get the idea