What's the cause of GPU panics on macbook pro mid 2010? I've had quite a lot of GPU panics lately, and after asking about it here and in other places, people told me that it is a problem with many macbooks from mid 2010. I've also heard that this happens when the mac switches from the internal GPU to the external, so I unchecked the 'automatic graphics switching" box in my energy settings. Still, the problem remains.

What I find so annoying is that the crashes are so unpredictable. I'm often using my mac for hours at a time, doing quite a bit of GPU intensive stuff like watching HD video. Because of my visual impairment, I'm also using the zoom feature, which I imagine also uses the GPU. But I can't see any pattern in it. What exactly triggers these problems, and are there ways to avoid crashes?
Suggested problem tracing /and repair) steps (after each test the performances).

Some applications will force use the Nvidia card (without automatic switching).

Yes the ZOOM feature adds stress to the GPU.


Vacuum clean the inside of your Mac to improve cooling.
Google and Install gfxCardStatus, Leave on Dynamic Switching. From there it will Monitor and Alert you to what apps switch you to the Nvidia Graphic Card.
Also open the Activity monitor - Energy tab, where you can see when the Nvida card kicks in, and does it switch on/off irregularly.
Monitor your Console log for irregular (fast)GPU switching.
Do some hardware testing: 



  GpuTest is a cross-platform (Windows, Linux and Max OS X) GPU stress
  test and OpenGL benchmark. GpuTest comes with several GPU tests
  including some popular ones from Windows'world (FurMark or TessMark).



worst case remove the Nvidia card, and go without it.