If you, change the graphics card (and add another one if you can afford it). I use 2 x 1080ti's in my main PC, it really does make a massive difference. I have a 1060ti in the other one and it is a lot slower. Good stuff, either way, at least you will be able to kick out some nice models with your set up!
As salex said though, bang in as much memory as your pocket will allow.