Question GPU upgrade

[Miltostak]

Hello guys. I am using my PC for video editing and soon I will need to be able to handle 4K RAW files that my current build struggles with:

AMD FX 8350
RADEON R9 270X 2GB
16GB RAM HYPERX
ASUS MA99FXPRO

In a few months I will do a new build from scratch, probably with a Ryzen CPU. My idea now is to upgrade my GPU and also get a water-cooling system so I can overclock my CPU. I need these two to fit my current build but also the one that I'm going to build. I'm not an expert with PC hardware so I'm looking for suggestions. Thanks in advance!

 

[MrN1ce9uy]

What power supply and case do you have?

 

[Miltostak]

Can't remember the power supply brand but it's around 750W, so no problem there.
My case is NZXT H440