The GTX 680 will be intentionally crippled for certain workstation applications. E.g. FP64 performance cut down to something like 1/8th of what the chip is actually capable of. The Quadro card probably also features things like ECC memory, which means it's less likely to have errors, etc. for when accuracy is a must.
In any case, AFAIK Nvidia gaming cards suck at things like compute, so you'd be better off with an AMD card or professional-oriented (Quadro, Firepro) card, which will have optimized drivers etc.
Or a Titan, which apparently isn't too hobbled.