I tested the Geforce GTX660 Ti for Cycles against my laptop GPU (Geforce 525M). It was abot 7 times faster. Not bad, I’m almost sure that Vray gives better result on an i7 CPU.
On the other hand I take back the 660 to the shop; in Unity3D editor it was not so much faster than my good old card, the Geforce 8800 GT. Shame on both Geforce and Unity developers.