what is best for gaming HD5850, HD6870 or GTX 560 ti

[Miloslav97]

currently using HD6770, is it worth to upgrade to any of this 3.gpus.
if is worth it what gpu is best ?

 

[yodudel]

I would say the HD6870 and the GTX 560 ti are your best choices. The 560 has a way better memory clock but the 6870 has a slightly better engine clock. Personally I would go with the GTX 560 ti

 

[Kekoh]

The GTX 560 Ti is the best upgrade out of those. It would be roughly 50% faster than your current HD6770. Just make sure you have an appropriate PSU. A quality 450W+ would be fine.