There is a serious performance hinderance in WoW on the MacBook Pro mid 2012 release and Mountain Lion and I wanted it to bring it to your attention. As it is probably software and hardware based, let it be known that this is a non-retina MacBook Pro, but it does in fact have a dedicated GPU.
Core i7 (Ivy) @ 2.3GHz Turbo 3.2 GHz (IIRC)
4GB DDR3 1333 MHz
Geforce GT 650M
I first want to state the performance issue was non-existant on Lion. Performance on High settings was very acceptable of about 50~70 fps conservatively. Basically the laptop is 2 days old, with one day being on regular Lion, and day two being on Mountain Lion. Post ML install, the performance is close to 67% of what it was prior to OS installation. I struggle to stay above 25fps at the exact same settings.
Note: Original gameplay was in clamshell @ 1920x1080 resolution for both OS versions. There is no AA enabled, and settings with the exception of AF were the streamlined "High" category.
I have already verified file permissions, re-installed World of Warcraft by downloader (fresh install of OSX and WoW), I have reset SMC, and I have reset PRAM/NVRAM, just to try and flesh this out.
Frame of Reference:
I am sitting right next to iMac 2011 (roommate) basically a 2.4GHz SandyBridge with a 6770M Radeon, settings on High, roughly 45~55 FPS. My current settings after also using identical with x16AF, is about 25~35 FPS. All benchmarks of the GT 650M do show significant gains over the 6770M. Hence the reason for purchase.
Monitoring temperature with atMonitor shows that neither the CPU nor GPU hit above 70c. This is terrible for me to see, but within the operating parameters of an Ivy Bridge and a Kepler104 based GPU. There is also a fan cooler under the laptop. I have switched from external monitor to internal lcd, with absolutely no change in performance including the fact that the resolution is 1440x900 instead of 1920x1080. Thats quite a significant reduction in megapixels throughput.
Reduced graphical quality to Low/Good, and despite this, it is still very susceptible to spiking. But overall playable in the realm of 35~45 FPS.