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TheSufle

macrumors member
Feb 13, 2019
95
46
I want to try a new mod, I ordered a fan, but due to the holidays it won't be soon

when everything comes, I will post a report here
 
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EngramAgility

macrumors newbie
Jun 11, 2009
28
0
Vermont
Think 10 times before you do something, first change the disc and thermal grease, do not glue the screen back so that you can disassemble it again, the hottest part is the processor because of the too small heatsink, this is what you need to think about how to improve it!
That sounds like a good plan. I just ordered some Thermal Grizzly Kryonaut to start out with.
 

wast

macrumors newbie
Feb 3, 2021
3
0
Regensburg, Germany
Hi guys,
i´m completely new here at MacRumors, but as is read this thread with great interest i decided to register and share my ideas with you.
I own a 2017 5k iMac with the 7700k which is known to get very hot. I don´t really work on the Mac anymore but i play games a lot on it.
Switching off the Turbo Boost already helped a little bit, but in the near future i will open the Mac to clean and renew thermal paste. (never cleaned it so after 3 years this might help a bit)
As is mostly use a eGpu i don´t really have an issue with the GPU. But the CPU peaks out at 100 C.
I like the idea with the two fans, but as mentioned before the main issue is the heatsink.
For testing i just ordered a used heatsink for 10 € on ebay.
I´ll try to find a radiator that fits on the CPU heatsink. It will just be a passive radiator that wont benefit from the fan.
Do you think this might be a problem when playing games for about 4 hours straight? Or will it still be better than not adding a radiator to the CPU heatsink?

My next Idea will be a lot more tricky. How about attaching a plug and play liquid cooler on top of the actual heatsink.
Something like this:


I´d make two holes with a milling machine for the hoses and attach the fan with the radiator somewhere at stand.

Let me know what you guys think about this idea.

Edit: 64,5 x 64,5 x 23,5 mm (L x B x H) These are the measurements for the cooling unit itself.

And some more ideas with non water passive cooling:




 
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TheSufle

macrumors member
Feb 13, 2019
95
46
buy a cooling system for your experiments, do not spoil what is inside now if something goes wrong!
 

wast

macrumors newbie
Feb 3, 2021
3
0
Regensburg, Germany
Thanks for the tip.
I ordered the Heatsink and a Ram Cover Lid.
Unfortunately its coming next week. So i did some more planning.


s-l1600.jpg
I want to attach a copper plate (red drawing) onto the cpu heatsink to create a flat surface.
Then i either would like to attach a liquid cooler or just another passive heatsink. Depends on how much space i have.
How can i attach the copperplate or the addional heatsink to the original one?


IMG_8301.jpg
Then i´d like to cut out the Ram Cover and attach a Fan.

Big question here: Should the fan blow air into the Mac or suck air out of the system??

I tried to just leave the cover off. Doesn´t make any difference.


IMG_8301 2.jpg IMG_8296.jpg
This is supposed to be a water cooler attached to the stand. The hosing is going through the ram cover an onto the cpu heatsink.

I hope you get my drawings.
 

wast

macrumors newbie
Feb 3, 2021
3
0
Regensburg, Germany
So here is a short update.

I attached two Noctua 40x20 5V Fans to the Ram Lid.
I plan to power them via a USB charger or even through one of the USB Ports from the iMac.

The only thing im not sure about is in wich direction the fans should face for the best result.

Today i received some more stuff to upgrade the heatsink.
I´ll keep you up to date.
 

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Buza

macrumors newbie
Feb 14, 2021
1
0
Hi Guys, a huge kudos for @AfroUSA and @TheSufle ?? I'm very impressed by your mods that you made, it looks like iMacs have plenty room for some good upgrades that can extend even more its lifetime!

My question to you is - have you checked if there are any benefits in terms of CPU and GPU benchmarks before and after the mod? I'm really curious how much your mods can boost the machine, especially I'm interested in Cinebench score : - )
 

TheSufle

macrumors member
Feb 13, 2019
95
46

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TheSufle

macrumors member
Feb 13, 2019
95
46
Help to find 5 volt in sata power
 

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TheSufle

macrumors member
Feb 13, 2019
95
46
In general, you need to look for a fan with a more suitable case

And better than 5 volts, there will be a lot of noise from 12 volts
 

Storm_VLC

macrumors newbie
Mar 4, 2021
7
5
Hi everyone I love this mod for our imacs, I'm going to make mine with the ideas collected, what I have seen is that when welding the double central fan, each one points towards one part, I have thought to cut the three supports that hold the turbine and stick it on the other side so that they are both on the same side, since I think that is where they should get more fresh air. Do you see it as a good idea? Or do I let each one point to the side?
 

TheSufle

macrumors member
Feb 13, 2019
95
46
this is a senseless undertaking, it can come off, I have already said many times, you need to solve the problem with the processor, since there is the weakest cooling
 

AfroUSA

macrumors newbie
Original poster
Jan 9, 2017
20
53
UK
Exactly, best will be to work on delid the CPU, get better thermal paste for CPU and GPU, than work on better air flow (like we did with dual air fans).
My unit is still working well, its now almost 3 years ;) No thermal resets or other throttling issues ;)

The main issue with this design is air flow and space (or lack of it)
The air is forced from the bottom to cool PSU, motherboard, HDD/SDD, memory modules, than goes through fan, where the air is forced into heatsink CPU/GPU!, than outside at the back. When you disturb this flow by other interior fan in the wrong place or wrong cutouts, all will be less effective.
TheSufle had excellent idea of making dual fans like in new iMac Pro. This give the air flow in our iMacs speed, hence more effective air flow.
Screenshot_20210304-231416_Chrome.jpg


Screenshot_20210304-233440_Chrome.jpg

So now each time CPU or GPU is working hard, fan blows double the amount of air, cooling iMac weak/small heatsink faster.
Its a bit lauder when on full blast, but I dont care ;) I can see flower leaves moving on window sill about 60-80cm away :)
 
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Storm_VLC

macrumors newbie
Mar 4, 2021
7
5
Thanks for the ideas, I am working on my iMac to improve temperatures, it is an i7 7700k, as is already known, very hot, at the moment I have made delid, and changed the encapsulation for one of copper and liquid metal, also substituted thermal paste of heat sink. CPU & GPU for liquid metal too, now we have to work with the ventilation
 
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AfroUSA

macrumors newbie
Original poster
Jan 9, 2017
20
53
UK
I also wanted to ask which area is the best to cut and weld the double fan?
Best will be to cut the red mark on the photo in fan from your iMac, than cut the same out from new blue fan. The yellow mark is a divider to make fans mix air flow better, simillar like in new iMac Pro twin fan.
p2MyvFHl.jpg
 

Storm_VLC

macrumors newbie
Mar 4, 2021
7
5
Best will be to cut the red mark on the photo in fan from your iMac, than cut the same out from new blue fan. The yellow mark is a divider to make fans mix air flow better, simillar like in new iMac Pro twin fan.
p2MyvFHl.jpg
Perfect, thanks
 

Storm_VLC

macrumors newbie
Mar 4, 2021
7
5
Thanks for the ideas, I am working on my iMac to improve temperatures, it is an i7 7700k, as is already known, very hot, at the moment I have made delid, and changed the encapsulation for one of copper and liquid metal, also substituted thermal paste of heat sink. CPU & GPU for liquid metal too, now we have to work with the ventilation
First results after changing thermal paste & delid, the results with the CPU in normal load, have improved remarkably, but the temperature continues to skyrocket when the workloads, for now it is phase 2, improve ventilation and add some heat sink, I attach an image of the result, I did not take a photo of the before ??‍♂️
 

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Storm_VLC

macrumors newbie
Mar 4, 2021
7
5
Here I present the work done to the iMac:
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Work done, double fan, delid with liquid metal, change of thermal paste Cpu & Gpu for liquid metal, installation of additional heatsinks on motherboard, heatsinks and memory.
Final conclusion, each thing that has been done has improved the system, the most notable change has been to change the thermal paste for liquid metal along with the delid, the ventilation improvement helped but the same degree of improvement was not noticed, really is that after all the work, it is still insufficient to control the temperatures of the i7 7700k, the original heatsink is not capable of keeping up, we would have to continue working on it, so I hope that if you get something good you will tell us here , for now I will leave the imac like this until I can make a new notable improvement, regards
 
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Storm_VLC

macrumors newbie
Mar 4, 2021
7
5
Finally I tried to add this fan of an Apple Air xtreme, but I could not turn it, if someone knows how to connect it to make it work, the idea is to connect it also to the sata cable of the hard disk
7944A5F4-340B-4419-A24E-0E88BECA5512.jpeg
 
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TheSufle

macrumors member
Feb 13, 2019
95
46
I also tried to run it and the imac does not turn on with it, it's better to use a 5v fan from a windows laptop
 
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