I was using a normal magnet, I hadn’t heard of the headphone trick but that works GREAT, and the magnet inside of them is so small I can guarantee it will not cause damage to anyone’s computer. (The one I was using up until now was a MUCH more powerful magnet.)

I keep a pretty harsh eye on my computer heat as well, the only other option is to run with the lid closed, which causes my macbook pro to run a couple degrees hotter. More heat dissipates through the aluminum top without it’s upward movement being blocked by the glass screen.

If you’re trying to decrease temperatures, positioning a box fan parallel to the keyboard and creating airflow across the top helps even more.

Thanks for the tips!

I have been in the industry at the hardware level for over 20 years and can assure you that this kind of a magnet doesn’t have even the slightest chance of causing you any grief. I’ve used magnets to erase hard drives and I can tell you that it takes an amazingly powerful magnet to actually do it. Hard drives have massively powerful magnets inside of them to move the actuator arm.

-Doc

But I don’t think much, if any, harm would come from a small refrigerator magnet being used as described here. There is already a row of magnets in the upper case of the MBP near the trackpad/lip edge. Those magnets are what you feel “grabbing” at the display assembly/lid as you close the laptop… they are what keeps the lid closed until you lift it again. Those magnets are also what the display assembly “senses” to know when to shut off the display. SO I don’t see how a weak refrigerator magnet could hurt the display. Although I don’t think it is as convenient as pressing ctrl+shift+eject.

The Mac already has enough trouble with gaming performance, but this is even more compounded when users hook up an external monitor, creating three problems:
1) Resolution: Higher resolution requiring more silicon horsepower.
2) VRAM: OSX splits the VRAM allocation between the two active displays, forcing the GPU to render a game with half the VRAM.
3) Overheating and Throttling: Clamshell mode, the only other way to truly disable the laptop monitor, decreases airflow, which leads to overheating, which leads to the system underclocking the CPU and GPU to cool, which leads to a choppy, unplayable mess that sort of looks like Diablo 3 on my Thunderbolt display.

Thanks for the magnet tip. Sounds like a winner!

You can say “be careful” all you want, but reality is people shouldn’t be offering advice that can be more damaging than helpful.