Gtx 960 2GB-4GB or R9 380 4GB

Hey guys!
Which one between gtx 960 2gb-4gb and r9 380 4gb is better?
Cpu: i5-4690
PSU: 620w 80+ bronze
Case: BitFenix Merc Alpha. Do they fit in my case?
There is a difference between 960 2GB and 960 4GB as regard UE4?

I think the GPU R9 380 4GB is awesome on UE4 :slight_smile:

Benchmarks looks like the R9 380 is faster.