My main pc right now is:

Nvidia 780 sli mobo
Intel q6500 2.4 ghz quad core
8gb ram (max for board)
2x9800 GTX+ in sli
650 watt psu
500 gb 7200 Root hdd
1TB storage hdd

i do have issues with it lagging after 4 windows, but i will be running 4 per pc.

should i upgrade this pc as well?