Avoid Computer Overheating on Graphic Intense Renders


Active member
:)Inspired by Swizl's and BillG's posts in the thread "More Questions about Required Specs for Laptops"
I decided to open this thread in order to obtain as much information about avoiding frying my Matchbook or iMac.

By using a cooling unit it looks like not only did BillG cut his render time in almost half but I bet he also saved wear and tear on his computer.:D

When I was trying to render a 26 second animated file (It had tons of particles in a particle Emitter to simulate rain) my computer was very very hot and the fans were blowing almost of the time.

:geek::love:Calling all beloved Geeks:
If anyone has more information on this it would be greatly helpful . . . hopefully to all of us.

If anyone used a cooling unit what kind?
Pros and Cons on the unit you use.

Granny Hugs 000
My Best Wishes to You
This is the cooling unit I bought: https://www.amazon.com/gp/product/B07CGMHP24/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1 It runs quietly, and has been pretty effective. It is made out of cheap plastic (polycrapolate, I think ;) ) but it feels plenty solid just sitting under my laptop on the table. There re lots of makes and models available, so a person can choose what fits their needs.

For what it is worth, I have now been rendering multiple animations for over 4 hours steady this morning (no breaks), and the CPU is staying between 650% and 750% on the activity monitor, and the kernal_task is hanging around 5% with occasional short term bursts. Prior to the added cooling I was lucky to get 400% CPU, and usually kernal_task was around 400%.

It feels like I have a new computer.

Bill in MN


Active member
Sounds like a good use of $30! I figured it would help having one of those, but I had no idea that it would improve performance that much. Nice topic thread indeed. Thanks for starting it Jeanny and for the testing BillG!

This is what my activity monitor looks like now. Previously, the graph was half or more red. Laptop is an early 2011 quad i7.

Screen Shot 2018-12-04 at 12.21.02 PM.png

Edit: I should mention that this is after 4-1/2 hours of non-stop animation rendering, balls to the wall, as they say.
For Jeanny with her iMac, I'll bet that a desktop fan blowing at the back will work really well to do the same thing, if it is getting hot. I guess that heat is the price that we pay for enjoying the small sizes of laptops and iMacs.


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@ Swizl:
Thanks for the compliment. It feels good to help in some way.

@ BillG
Thanks for transferring your information to this new tread.

Granny Hugs000
My Best Wishes to You


Active member
I think BillG Has the right idea as you could move this to be used on more than one laptop. And Thanks Jeanny for starting an interesting topic.
Here is what I use a pieced together cooling rig. Actually not very noisy. But BillG's is probably quieter. Anyway I've been using this for years. Cooling Rig.jpg
For my iMac, I have one of those vertical dyson heater/fans. In summer I place it on the desk to the side of my iMac so that blows cool air across the front and rear of the display. This helps to keep the iMac cool. For my laptop, the rubber feet had fallen out, so I replaced them with the self adhesive pads that are sold for putting under furniture legs. They add a bit more height and improve convection/air movement under the laptop. I used to use a usb fan and direct that onto the laptop or onto iMac display to cool it down.


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@ uncle808us and @ Chris Heat

:DThanks for the some more good ideas!
I’m thinking it may be a good idea to use all the posted cooling methods together.
It would be just my luck the computer would form icicles.:giggle:

Granny Hugs 000
My Best Wishes to You
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Well-known member
* Well: FWIW:
* I have build a large aquarium into which an iMac 27" easily fits.
* Filling it with cold beer (add a few ice cubes and your favourite herbs and spices) works perfectly well. Adding a few arctic gold fish is recommended during rendering. Finally, insert a nice flexible drinking straw.
* Note that this won't prevent your iMac from overheating :mad:


Active member
:giggle::giggle::giggle:What a great way to start out the Day!
Thanks for the laughter Helmut!
Your post actually gave me a belly laugh that surpassed even Santa’s.:LOL:
It was smart to add a “Disclaimer” of sorts.
It seems in todays technology nothing is impossible . . . :alien:
thus one might take your post serious and give it a try.:eek:

I thought my husband could use a good laugh so I shared your post with him.
He also had a good laugh over it :LOL:. He requested that I reply to you on his behalf.
He said that your idea was the best idea of all.

BTW: I'm not up with the new language of today.
What does FWIW mean?

Granny Hugs 000
My Best too You