I would get the r9 280x as 2GB VRAM is going to start to show some bad limitations and 3GB will overtake it as the recommended amount. The 4GB 770 is pointless as it is too expensive and also the GPU is not powerful enough to fill that 4GB so I would avoid it. Also for 1080p 4GB is a bit too much anyways and you could definitely save money and hassle by not going for the 770 in general and going for the 280x .
quick solution. great