I will soon have 970 SLI in my system (X99, 5820k, 16GB RAM) and have a 670 4GB from my old PC that I'm debating either selling or using as a separate PhysX card. Is it worth using as PhysX? Does this actually bring any real benefit in a 970 SLI set-up, or would it just consume more power (I have an 850W PSU) and not offer anything significant in terms of cost/performance benefit, therefore better off selling?