I currently have in my possession a gtx 780ti and a r9 290x. i also have a 75hz freesync monitor. I am wondering which one i should use.I want to know which is better due to fps, heat, noise, and extra features if that is possible.
Well you have a FreeSync monitor so if I was you I'd probably use my 290X. Also, AMD cards age really well. Tho the R9 series with a crappy cooler sounds like a jet engine under load, uses upwards of 300W and produce a ton of heat. Nothing that the 780Ti wouldn't do, it's also a toasty chip that is very power hungry!
290X. 780ti is a fine card but due to major console using AMD GCN many new games are being optimized for AMD GCN first. This lead to the talk about how AMD optimized their older card more than nvidia which is not the case.