Moriarty Avalon

Evening all, with Christmas and Black Friday rolling around its time for my annual "Do I need moar" brain drain. Specs are below, just looking for the largest single improvement I can make to this setup. Obviously want to push KSP faster but also looking with an eye to XCom 2 (squee!) Gigabyte GA-MA770T-UD3 AMD 770 AMD Phenom II X4 555 Black Edition 3.2GHz Socket AM3 6MB Cache Corsair 8GB (4x2GB) DDR3 1333MHz Memory Kit Unbuffered CL9 XFX HD 5770 1GB XXX Editon GDDR 5 Arctic Power 700W PSU