As previously said, I'm just selling my nVIDIA / PNY Quadro M5000 because no utility for me yet...
Thats a real monster which is able to display 4x 4K screens in realtime and of course works very well on Visualize rendering
Here the ebay link
The regular target price on market is +2500€, starting price here at 1500€.
All the specs here (last Maxwell GPU architecture)
Don't hesitate to contact me for any question!