Got a tip for us?
Let us know
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
iMac 5K - 4790K, M295X - thermal compound + second SSD upgrade + Air Vents MOD
- Thread starter AfroUSA
- Start date
- Sort by reaction score
Hello, how modified radiator? very interesting, i have i9 9900k i want to cool it down without adding a second cooler.
After 4y of my first MOD, my iMac 5K still works great, my son still use it for school and gaming with PUBG and BeamNG 👏😆
This is a fantastic, delightful thread and an ingenious series of mods series you engineered for your iMac 5K. My jaw dropped when I saw your case mod for more air intake.
Your mods are also a kind of visual road map for those of us with iMacs from this post-2012 form factor series who, likewise, are planning for making similar mods. This thread has all the hallmarks of the kinds of stuff we love to do over on the Early Intel Macs and PowerPC Macs forums. So it’s refreshing to find that over here on the iMac forum.
Now I’ll be pondering this case mod for my A1418…
Regarding the dual fan mod; I'm about to pop open a 2020 27" iMac i9 and delid; I don't believe there is any SATA power to "borrow" from ruling that out. Thoughts?
Having totally disembowelled an iMac 27 (whilst turning it into a monitor) it seems to me, as was repeated earlier in the thread, that the cooling system is throttled by:
1. The extremely basic (thin section) nature of the heat exchanger copper-work in the fan airflow.
2. The pressed contact minimal-weld junction from the copper transfer heat pipe to the h-e copper blades.
2. The small cross-section of the heat pipe to the heat-exchanger.
4. The small size of the actual CPU heat sink.
and lastly - very lastly
5. The ability of the fan to pass air through the heat exchanger,
To solve 5. you don't need a double fan.
You just need to make the existing fan work faster.
The iMac Pro has a double fan because its heat exchanger is about 4x the size, with 4 heat pipes.
In my very inexpert opinion.
It looks like the only place to get 12v is from the PSU.
If you know what you're doing...
1. The extremely basic (thin section) nature of the heat exchanger copper-work in the fan airflow.
2. The pressed contact minimal-weld junction from the copper transfer heat pipe to the h-e copper blades.
2. The small cross-section of the heat pipe to the heat-exchanger.
4. The small size of the actual CPU heat sink.
and lastly - very lastly
5. The ability of the fan to pass air through the heat exchanger,
To solve 5. you don't need a double fan.
You just need to make the existing fan work faster.
The iMac Pro has a double fan because its heat exchanger is about 4x the size, with 4 heat pipes.
In my very inexpert opinion.
It looks like the only place to get 12v is from the PSU.
If you know what you're doing...
Last edited:
Not necessarily. USB is certainly an option, however, I really despise the idea of running a cable back into the case from the exterior and USB powered fans aren't exactly as powerful as tapping that SATA power previously available; a USB powered "double" fan isn't likely to match the sheer RPM of the existing single fan is one of my concerns.
I've never in fact worked on an iMac, everything else though and I've worked on a TON of Mac Pros, Mac minis, MacBooks, just never had to crack an iMac open by sheer happen chance.
I'll say every Mac I've run into, has had cooling problems with the stock paste. Just swapping it out for either a higher quality paste, or especially Liquid Metal, even with under powered cooling, is life and death difference. My 2019 MacBook and Hades Canyon in particular are direct die, those man on man, love Liquid Metal...
Carolina Reaper (OC'd Hades Canyon NUC w/Ubuntu, SK Hynix, Mushkin REDLINE and "Killer WiFi"): PC Talk Forum: Digital Photography Review
Expert news, reviews and videos of the latest digital cameras, lenses, accessories, and phones. Get answers to your questions in our photography forums.
Still need to do a write up on Liquid Metal on my 2019 MacBook Pro. In short, on bursty loads, it permits substantially higher results (25%, think Canon DPP4). On more threaded loads (think sustained 100% use), it's closer to 20% performance lift (think Handbrake).
That said, I can tell you right off the bat, I'm not going to see huge gains here. How do I know? Simple, the air coming out the back of my unit is already "warm/hot" If your fans are going full power, your system shows hot in the monitors, but the air coming out is cool? You've got bad paste. This system I have that's not the case, however, part of that is the 9th and 10th series CPUs are solder again, but I guarantee you that paste is toothpaste from the IHS to the copper. I can see my TVB kicking in and kicking back off real fast due to the 100C hitting on a core, when it kicks in.
Below is handbrake, x264 on Placebo, fans at max. 126W on the package, is pretty good btw. I think I can hit 4.3 on all core though, if I delid this puppy.
Last edited:
@thetechhimself: "......delid this puppy" - can you please clarify this please for many overseas readers and myself (a native English speaker).
Der8auer: Intel's Core i9-10900K Runs Eight Degrees Cooler With Liquid Metal
STIM is better than TIM, but liquid metal is better
Requires I tear apart the iMac to get to the processor, which is going to take some time.
Finally got around to opening the iMac (removing the LCD adhesive and removing the "guts"), getting the IHS off, and am waiting the 10-15 minutes for the STIM to be consumed by the quick silver.
Notably, there's some STIM smear that shouldn't on PCB... Hopefully the face of the CPU isn't damaged (when I used the delid tool to remove the IHS) when I clean it shortly. If so? That's a couple day delay to order a replacement CPU. I'd rather not though as I highly suspect Apple may be undervolting the i9 in the iMac 2020, just like they did with my i9 in my MacBook now; replacing the CPU with say a prim and proper i9-10900k instead of the i9-10910 which based off my research, is really a rebranded i9-10850k, may result in the loss of undervolting profile support, which would impact my multicore performance adversely, which I noted from the limited GeekBench's that are truly iMac 2020's out there (and not "hackintosh") that the single core although better on the i9-10900k, the multicore is not, which is what I'd expect.
I'll say this has been a challenge. It's proving as difficult as the 2019 MacBook Pro I'm typing on now where replacing the battery, and swapping out the paste for Liquid Metal at the same time, took me upwards of 6-7 hours. I'm on par even though I've been stop and go this round instead of all in one go. Wish me luck getting this all back together in one piece.
Notably, there's some STIM smear that shouldn't on PCB... Hopefully the face of the CPU isn't damaged (when I used the delid tool to remove the IHS) when I clean it shortly. If so? That's a couple day delay to order a replacement CPU. I'd rather not though as I highly suspect Apple may be undervolting the i9 in the iMac 2020, just like they did with my i9 in my MacBook now; replacing the CPU with say a prim and proper i9-10900k instead of the i9-10910 which based off my research, is really a rebranded i9-10850k, may result in the loss of undervolting profile support, which would impact my multicore performance adversely, which I noted from the limited GeekBench's that are truly iMac 2020's out there (and not "hackintosh") that the single core although better on the i9-10900k, the multicore is not, which is what I'd expect.
I'll say this has been a challenge. It's proving as difficult as the 2019 MacBook Pro I'm typing on now where replacing the battery, and swapping out the paste for Liquid Metal at the same time, took me upwards of 6-7 hours. I'm on par even though I've been stop and go this round instead of all in one go. Wish me luck getting this all back together in one piece.
Just an update, completed the delid conversion, without cooking the CPU. I am seeing an increase in multi-core performance where particularly, the machine will now punch 150W, continuously where before that kind of load would thermal throttle the system. Like my Intel Hades Canyon NUC, I'm now power throttled, appears the iMac 2020 won't push more than 150W on the i9-10910. Getting 14026 vs 13639. Not exactly a huge lift like I was expecting, but it "worked". The dip in power use was due to CineBench cycling benchmarks, but before delid? I couldn't get this guy to hold 150W draw on the CPU, let alone hit it.
![CineBench Post Delid.png]( "CineBench Post Delid.png")
WOW! A ten core machine. I am kind of old school here and not used to such high core counts in only one single CPU. First of all congratulation for your excellent tun up action described above. As a gamer, I'd say every drop of performance counts, especially when it comes to good AAA titles like Cyberpunk and later titles. As an absolute Intel Enthusiast, its mind boggling to me to run an i9 in the iMac. Even the non "K" version was super sexy in a time when just a year before introduction, next to nothing could top the i7. I am sure you can TURBO charge along in many Games with that great "Last Edition" Intel iMac. Keep rocking that i9
My kids are gonna run Minecraft and I run Canon DPP4, Intel only btw on the latter.
Plan to do a full write up on the process, before after, etc.