Delidded i7 7700k 27” iMac temps

[Andy5Kimac]

So I just recently upgraded my 2017 5k iMac to i7 7700k delidded with Liquid metal (thermal grizzly conductonaut) between the cpu die and IHS. Used nail polish to protect the transistors then resealed the cpu with gasket maker (used a very thin layer on 2 sides of IHS). Now before anyone flames away about how dangerous liquid metal is and delidding voids your warranty. I bought this delidded cpu used. Anyhow I then used Arctic MX-4 on IHS to Heatsink. My temps while idle ranges from 35-40C and when running Cinebench r23 it hits around 93-94C degrees. When rendering 4k video with FCPx temps shoot up to 95C and when exporting 4k video it hovers around 85C with the fans at full blast. Just wondering did my delidding worked? Seems like my temps are still quite high under heavy cpu load and I only lowered by few degrees.

 

[Andy5Kimac]

Also to those who want to upgrade their fusion drive to ssd the OWC thermal sensor cable is not needed on 2017 gen iMac. I also upgraded my fusion drive to 1TB NVME and WD blue 2TB Sata 3 ssd without the thermal sensor. Fans do not ramp up without it. Just FYI

 

[TwoH]

Unsure about the delidded CPU to be honest, not something I’ve really had an experiment with. But you are right about 2.5” SSDs not needing the OWC thermal sensor. It doesn’t just go for 2017 though, goes for the whole slim line (2012 upwards).
Only need the sensor for a non-Apple HDD

 

[Andy5Kimac]

Unsure about the delidded CPU to be honest, not something I’ve really had an experiment with. But you are right about 2.5” SSDs not needing the OWC thermal sensor. It doesn’t just go for 2017 though, goes for the whole slim line (2012 upwards).
Only need the sensor for a non-Apple HDD

Yes I seen so many YouTube videos on ppl upgrading their fusion drive and using the Thermal sensor cable. It’s not a cheap cable which doesn’t have to be used. Also I would say upgrading from my i5 7600k cpu to the i7 7700k was so not worth it. My i5 fans barely came on unless I encoding/rendering a long video. Even building 1:1 smart previews for wedding projects in Lightroom it never came on but since I upgraded to the i7 it comes on anytime I tax the cpu heavily... oh wells I only upgraded the cpu cuz I got it for cheap... though I cut my render times significantly but I kind of regret it lol. After doing some research on a stock 2017 i7 27” iMac temps, for delidding the cpu and using LM I would say I probably only downed the temps by 5 degrees tops. Delidding would benefit pc more with better cooling for sure. Don’t think it’s worth all the trouble on a iMac... lol

 

[jefnot]

Also to those who want to upgrade their fusion drive to ssd the OWC thermal sensor cable is not needed on 2017 gen iMac. I also upgraded my fusion drive to 1TB NVME and WD blue 2TB Sata 3 ssd without the thermal sensor. Fans do not ramp up without it. Just FYI

i don't think this is a huge issue since you can control it with a simple gui app SSD Fan Control.app at exirion. i pull hard drives from every model of imac and just load this to control the fan.

 

[Andy5Kimac]

So I just did the terminal cpu stress test on my delidded i7 7700k (with Thermal Grizzly Conductonaut) 2017 27” iMac and hit 95C. I did the stress test for 10 minutes and the temps wouldn’t get any further. I guess it’s safe to say my delidding worked but for max temperatures under maximum load I was hoping it would be in the 80’s. Though there is a improvement of 5 degrees cooler as I researched on other stock i7 2017 iMac under same stress test they hit 100C here

https://www.google.ca/amp/s/forums.macrumors.com/threads/imac-27-2017-i7-7700k-temp-hits-100-under-cpu-burn-test.2222394/?amp=1

Delidding with LM definitely benefits a PC more with better cooling then doing it to a iMac... I’ve seen users online who’ve delidded their i7 7700k with LM on a PC with good cooling get results of 20-30 degrees cooler. I just wish there was a way to upgrade to a better cooling system for the iMac so we can see similar results lol

 

[Andy5Kimac]

So I did intensive testing on temps on my iMac while editing 8 min 4K video timeline with lots of 3D titles and effects. My temps were:

h.264 better quality : 75-80C
Pro Res 422HQ: 80-85C
Transcode footage:88-90C
8 bit RAW 4:2:2 footage (color graded, 3D effects and multiple luts applied) : 65C

So I have not yet seen it hit close to 100C. So I would say my delidding with Liquid metal worked very well. I’d say if u want to keep the temps down delidding the cpu is a must and replacing the stock Intel TIM (toothpaste) with higher quality thermal paste would help with the overheating issues. Though the temps were still high in the pc world but for a Mac with poor cooling design it’s a huge improvement. Most importantly it doesn’t thermal throttle.