Benchmarking OpenSubDiv settings?

I just installed upgraded my K2000 to an M4000, the K2000 was pretty limited and did almost everything on my CPU.

I was wondering what would be the best method to cross-reference OpenSubDiv performance across the various compute settings?

I am not really sure at this time. I have just been upping the subdivision levels till it starts to lag in viewport rotation, then changing the settings to see if I can tell. I would like to know this as well, but I would really like OpenSubdiv to be completed soon. It really bothers me that I cannot Apply OpenSubdiv to a mesh.