one of the cards in my 7950 crossfire setup seems to be going bad. would a single rx480 be able to do the job as well as my two old cards? or would i have to consider crossfire with two? or consider an nvidia of some sort?
i like to play shooters such as battlefield and titanfall at 5760x1080.
An RX480 is about 50% faster than a single 7950. That means crossfire 7950 are faster, slightly, than a single RX480.
A single 1080 is faster than crossfire 7950 though. Still a single 1080 is $500+ where as crossfire rx 480's can be purchased for under $400 for even the 8GB versions. If going the 4GB versions then the price can be under $300 for two if looking for the best deals.
It really depends on your budget and what you are wanting to put up with. Able to spend $500 on a new video card? Go for the 1080. If you can only muster around $400 or less then go for dual RX 480s. Unless you really want a single card then a 1070 which is also selling for under $400. However, crossfire RX 480's will be faster than a single 1070 for about the same price. Some people really hate multicard solutions due to extra heat, noise, and power draw. However, since you are currently using a multi card solution I don't think you have a sensitivity to those as much.
At higher resolutions the RX 480 are going to be more than a bit faster than 1060 cards, so I wouldn't bother with those.
I really think it boils down to either getting crossfire RX 480 or a single 1080 for you IMHO.