Yes, I've been doing multiple tests on the same machine (Mid 2013 27" iMac), but booting from different hard drives (some with different versions of OSX/MacOs). The hardware score changes as expected but the graphics frame rate doesn't.
I've just added an SSD to my Mid 2013 27" iMac which has given me a nice increase in write speed, however I see that the '3D frames per second' score is significantly lower than it was when the computer was new. (544 vs 1369). So before I start looking for other reasons as to why this might be, has Novabench changed the way the graphics test is done? Is my graphics card really performing that much worse?