the gtx 770 won't have h265 features like the gtx 960. the gtx 960 does, but premiere currently won't use those features. its anyone's guess when they will modernize to use gpu encoding/decoding. if you are just after performance, the gtx 770 will be slightly faster. if you want a card for future proofing, or better features, or lower watts, the gtx 960 is better.
Unfortunately, Adobe does not currently support hardware GPU encoding or decoding at all. Even the most recent release of Premiere CC, 2015.2, decodes and encodes entirely using the CPU.
As for the GTX 770 versus the GTX 960, the GTX 770 is faster overall than the GTX 960, even in the current version of Premiere Pro CC. That's because the 770 has far greater memory throughput than the GTX 960: twice as much (224 GB/second versus 112 GB/second).
thank you for answer.. i think i'll go with 770 4gb that is a little bit cheaper than 960 4gb (in used market)..