You should be thinking about the consumer version coming soon, if you plan on getting one. 780 is probably not enough, but who knows? You better wait if money is a real object, and see the reviews of users with various setups. 780 is enough for a dk2, but CV1 will be much better, and supposedly requires at least a GTX 970. Currently I think the 780 is even more expensive than a 970, don't know why. Personally, I'm planning to get a gtx 980, unless something changes by next spring.
i7-5820K @ 4.2Ghz, water cooled, Asus X99-Pro USB 3.1, 48 Gb DDR4 2400, Samsung 950 pro M.2 SSD, GTX 980 Ti SC, 750w psu
That being said, it also states: 'In addition to the minimum spec it is recommended that your dedicated graphics card be capable of running current generation 3D games at 1080p resolution at 75fps or higher.'
I have a GTX 660 and it just barely BARELY cuts it. I can run most apps in the Rift acceptably as long as the graphics are set to low. You will probably not get satisfactory results with a 650...
been stuck on a 650 for quite a while, did the job but am finally getting my 970 next week and it couldn't come fast enough. a 650 will currently run but I'd invest in a 970 and the appropriate system as who know if some architectural change will mean a 970 minimum but either way I loved my 650 for keeping me in the loop this long, but can't wait for a 970 so I can experience judder free and more immersive experiences on a larger scale than the 650 allowed for.
It may technically work (in fact, it is the oldest Nvidia card that will even be supported at all), however, performance will likely be slow or choppy for many demos. It's recommended to use a GTX 970 for the best experience.