amd r9 380x or r9 390 for ue4 development?

hello, i have an amd radeon 7970 hd video card, i want to upgrade my video card on January, i’m thinking on buying one of these cards amd r9 380x or r9 390.

my question is simple, the amd r9 380x will work fine with all the demos and learning assets from the marketplace or i need to choose the r9 390 instead ?

right now my amd radeon 7970 hd has done a good work, i can use all the assets and is working without any problem in my ue4 project .

thank you in advance for all your advises.

The 390 would be more powerful

thank you darthviper107