i am new to the forum, and needing your help.

I currently run GTX 570 for video editing in PremierePro CC 2015. Would like to upgrade my GPU ( budget about 300$).

For that i can get usen GTX 780 (about 240$) or used GTX 970 (about 300$).

But i dont know wich one to buy.

I know the 970 is newer card, but specifications (more cuda cores, 384BIT goes to 780).

I am not into gaming (sometimes i play but games are not important), i just want for Premiere Pro to run faster (rendering)
My other specs are:

Intel i5 2500
16gb 1333mhz RAM
Samsung EVO SSD

Could you guys help me out.