I think gpu memory size is not a big deal, K5000 has only 4G if I remember.
Google nvidia k serie newegg on youtube, you will get a nice video to
explain what's the difference between pro card and gaming card.
Of course one of the reasons why these guys make k series sound so
professional is because they are expensive. But some points are good. This
is just like registered memory vs unregistered memory. It all depends on how
valuable your work is.