jarno’s right if your only using one screen but if your using 2 or more then you do need a better graphics card but I have owned the hd7770 and only used it for a couple of months as it was a bit laggy and the hd7790 (asus chipset) preforms a lot better .
This is not a gamers comp ,it is purely a DAW and that’s all it will ever be but running HD graphics on 3 screens with Cubase 7 is a dream .
anyway good luck with your build !
john