Macbook Pro GPUs: overheating and noisy fans
I'm sure everyone with a Macbook Pro has experienced the heavy heating and the fans sounding like they are about to take off.


Sure, but depending on what the Macbook is doing it could be normal behaviour.
Also some Macbooks heats more than others. What's yours?

Anyway, there are two possible situations:

1) you always experienced heating and loud fans:

I would say it's normal behavior (but you can always try what suggested at (2) if you feel it's really too much heat/fans)

2) heating and lound fans started at some point during the life of your macbook:

Try to fix the problem


make sure the macbook can cool down normally (fans exhaust grid are not obstructed)
reset the SMC (see other answer)
use Activity Monitor to check if there is a connection between overheating and specific application/processes
bring the macbook to apple service center





  My problem is that this is happening even with simple tasks such as web browsing or watching a video...


Web browsing pages that use Flash or intensive JavaScript and/or watching videos can be CPU/GPU intensive tasks.




  My understanding is that it is due to the Intel CPU doing all the work to save energy. Am I wrong?


Yes, you're wrong.

Macbooks Pro have an integrated GPU (integrated into the CPU) and a discrete GPU.

The difference between the two is that the integrated GPU heats less, drain less power but has limited features and computational power than the discrete.

When possible the OS uses the integrated GPU to save energy. When not possible (ex. you're using photoshop, you attach an external display,... ) the discrete is used and the MBP heats more.

You can see what GPU is used with gfxCardStatus

The Energy Saving GPU option tells the OS that you want to use the integrated GPU whenever possible.