Gtx 670= 2gb vram 256bit 920mhz turbos to around 1050mhz i do believe
amd 7970=3gb vram 384bit 920mhz no turbo (or ghz editon which i think is like 1050mhz?
Higher resolutions amd definitely . both are great cards that run pretty much any game on ultra with decent settings (except witcher 2 with ubersamplin) the 7970 ghz is currently the fastest single gpu in the world right now proof? http://www.tomshardware.com/reviews/radeon-hd-7970-ghz-edition-review-benchmark,3232.html http://www.tomshardware.com/reviews/radeon-hd-7970-ghz-edition-review-benchmark,3232-19.html
so yea if you want to have the honour of owning the worlds fastest single gpu get the ghz 7970 and make your friends cry. dont say the 7970 isnt the fastest i put those benchmarks there for a reason. and dont tell me you can oc the 670. same can be done the 7970. just my 2cents both a great so cant go wrong with either