Hey, fellow extraterrestrials. I've recently been having a world of trouble with the HD5970 in my 4 - year old Aurora and was looking for some upgrade advice. 

The two cards I've been looking at are the R9 270x and the GTX 760. When comparing the two cards I've noticed that the Nvidia is cheaper and performs better, which should make it a no brainer. I'm just curious if I'm missing any critical details or things I should be taking into consideration.

Also, will I have any issues if I go from my ATI card to an Nvidia one? What would be the best course of action when doing so? Thanks in advance, all.