I am deciding between getting another r7 370 to crossfire or selling my current r7 370 and getting a rx 480 8gb. Which is better in terms of performance? I can't seem to find any benchmarks comparing the two.
You'll probably get much higher fps with a single RX480 anyway (around 15-20% or more), especially in newer games. No reason not to go for the RX480 if you want to be good for a few more years. CF is more commonly implemented in DX12 games, so once you run out of gaming power in a few years, you can easily add an RX480. But for now, there are still a bunch of games not supporting CF setups properly.
While it should actually be easier to implement though... Anyway, we're still in the early days of DX12. Better scaling problems than all the microstutter (caused by varying frametimes) and all the shit we had with DX11 for years..