It's a 15" rMBP with a 2.3 GHz i7 and a GT 650m. I was looking at the task manager while playing games, and it appears that the CPU is getting downclocked significantly. This has a large effect on the performance of the games, and I don't know how to fix it. I originally noticed it in Black Mesa, but I just saw it in Skyrim too. It makes the framerate drop a lot and makes it really stuttery/choppy. it usually drops down to around 1.2 GHz, but I saw it go down to about 0.7 GHz in Skyrim. Does anybody have any ideas on how to fix this? I already tried changing the processor power management settings. I'm using Lubbo's Fan Control to keep the fans on 100% I'm running it off a Thunderbolt external hard drive, if that matters. Any suggestions?