My 2010 Mac Pro has a Nvidia FX4800 graphics card installed. Lightroom 6/CC2015 can use Graphics Processor Acceleration to speed up and make controls more responsive in the develop mode.
Despite it having Open GL 3.3, the FX4800 is one of the cards that Adobe do not support with Lightroom's GPU acceleration.
So I guess the question is, for those that have cards that support it, firstly, which cards are they, and secondly, does it seem to make big difference?
Separately, I tried to install Color Finale yesterday (for Final Cut Pro) and it needs OpenCL 1.2, while the FX4800 only has 1.1...