Ok all three of these cards are in my budget but i have 3 monitors and i want to know witch one will perform better because i know that because i have 3 monitors the extra vram might help. wtch one will best serve my purposes I probably will be playing steam games starcraft battlefield and planetside 2.
IMHO, The 7970 should be your primary choice, thanks to the driver update that boosts its performance compared to Kepler GPUs. Not to mention, the higher overclockability! It'll be perfect for a multiple-monitor setup.
Kepler GPUs are pretty bad Overclockers compared to ATI's Tahiti 7000-series! The only reason you should go for the Kepler series is because of its Power saving features. And, Ironically.. these very features reduce the OC'ability of the Kepler-series.
I myself have a 660ti, But the only reason i picked it over a 7950 is because i was getting a free copy of Borderlands 2 at the time. But now and then, i feel like i should have picked the 7950 (or the 7870 even!)
I'd suggest going with the 7970 because at this price.. its got One Major Blessing: Horribly Amazing Value!!