In our recent review of the late 2013 Mac Pro , one of our sticking points was the OpenGL performance that trailed Windows on the same hardware. A particularly damning case was the high-polygon-scene performance in Autodesk Maya showing how OpenGL viewport 2 performance fell off a cliff when you pushed into very high polygon counts of over 20 million with the D700 in OS X.

While this issue still needs to be resolved for some programs like modo, some quick sleuthing by Apple and AMD shows that the problem was on the Autodesk side. Maya was not simply querying the GPU RAM; for some reason, it was using a hard ceiling on OS X, so the brutal performance hit was the result of that ceiling. Once you explicitly tell Maya to use your available VRAM with the environment variable MAYA_OGS_GPU_MEMORY_LIMIT=6000 in ~/Library/Preferences/Autodesk/maya/2014-x64/Maya.env , performance is perceptibly the same as in Windows in Boot Camp with very large scenes:

Up to 72 million unique polygons and very good performance on OS X.

72,000,000 polygons and still responsive on Windows 8.1.

I could have gone higher than that, but 145 million polygons pushed me past the RAM ceiling of my 32GB Mac Pro. It will be rare to hit that polygon count in Maya because people use render-time displacement maps, memory-efficient instances, and render proxies (low resolution stand-ins that render at full resolution) for giant scenes like forests. Actually, all you have to do to see full resolution and 300 million polygons for a scene like that is to use memory-efficient instances that are GPU-aware:

width="640"]330-million instanced and lit polygons with the FirePro D700 on OS X.

If you have a GPU with more than 1GB of VRAM, I highly recommend setting this environment variable to your GPU's VRAM amount. This issue will reportedly be fixed in Maya 2015, but Maya is clearly an absolutely massive program with some annoying issues—here is my blog post on how to fix Maya performance when the Help Line is visible in OS X.

So, fellow Maya users, I just need to implicate Apple in another 17,000-word article about our other bugs, and we'll have them fixed in no time! This brings us to the question of why I thought to blame this on drivers and not the Mac Maya version to begin with. It's odd that this Mac-only hard-coded VRAM amount existed at all because Maya is very much the same beast on all platforms, and from my knowledge of it as a beta tester, platforms don't get specific attention for tuning, and that's the case for the dominant platform as well. That's why I assumed that this was a driver bug and not Maya-specific.

Anyway, we'd like to thank AMD and Apple for their quick work with Autodesk to resolve this issue. We'll be updating the review today to account for this new information.