The "K" series Quadro cards are never and different than the non-k cards.
Here's a link to Nvidias website showing off the K series, in the bottom it says "PREVIUS GENERATION QUADRO GRAPHICS SOLUTIONS", click it and you'll see the names of the non-k cards. http://www.nvidia.co.uk/object/quadro-desktop-gpus-uk.html
and the K series is most likely the faster one when comparing the same named cards etc. K2000 vs 2000.
The "K" series Quadro cards are never and different than the non-k cards.
Here's a link to Nvidias website showing off the K series, in the bottom it says "PREVIUS GENERATION QUADRO GRAPHICS SOLUTIONS", click it and you'll see the names of the non-k cards. http://www.nvidia.co.uk/object/quadro-desktop-gpus-uk.html
and the K series is most likely the faster one when comparing the same named cards etc. K2000 vs 2000.