Just a heads up.
I can confirm this,for me disabling the Vray for Rhino 2.0 plugin resulted in a 3x speedup of Opengl performance on Gtx 580/3gb
-discussion and others tested it .
long thread-
http://discourse.mcneel.com/t/holomark-2-released/8040/273
-also double-sided polygons effects performance… which you can turn off with a tweak in rhino.
http://discourse.mcneel.com/uploads/default/11708/f2336de51b76d6e0.zip
If anyone has any solid info why a plugin would do this to opengl would be very much appreciated,and I will pass it along.