Why Nuendo uses 2nd GPU in OSX?


I’m constantly using Nuendo with my laptop and now trying to make a change towards OSX with my Macbook Pro, just testing it out. Just wondering, why does Nuendo force MBP to use AMD GPU in my late '11 MBP? I would imagine Intel HD 3000 would certainly be enough to run simple graphics Nuendo uses. It’s no 3D game.

The reason I’m asking this is the amount of fan noise which is often present when AMD is in use. I’ve tried to slow down MBP by using only one CPU with hyper-threading, but still the noise is quite loud. The funny thing is, when using Windows7 (which doesn’t even have the possibility to use Intel GPU, Apple doesn’t allow it) I’m still able to get Nuendo use silent when I restrict CPU power to 50% in Windows Power Scheme. There’s obviously less CPU horses available, but 99% of my work can be done with this setup (even working with VSL MIR Pro) and I can also record beside the laptop without any noise leaking in from the fans.

So, Nuendo in OSX seems to tax system more, at least when it comes to fan noise, whatever the CPU core combination. Just wondering if Nuendo would use Intel GPU, would it be more silent in OSX? Is there a specific reason why AMD kicks in?