960 4Gb.. not huge performance gap between 950 and 960. 4gb wil only help at higher resolutions and intense graphics...
i would suggest a r9 380 4gb... has slightly more performance than 960 4gb and is also lower in price, performs better than competition at 4k too... but consumes more watts thats only drawback of r9 380, still i would chose r9 380..
gud luck building..
dnt 4get 2 select d bst ans...