27” iMac 5K 2019 CPU upgradable Or soldered?

"iMac 27 2019

Can be upgraded to i9-9900kf or i9-9900k

I9-9900kf has better performance.

Can be upgraded from 3.0 base model to 3.7 high end model.

I done it 3 times already.

Remove battery from mother board on 3.0 base model while installing i9-9900kf

After install reinsert battery.

Update (10/26/2019)

here the proof"

"The 27” iMac’s have always had socketed CPU’s. The 21.5” models low end models often had soldered CPU’s

But! You have been limited by the EFI to the CPU’s within the series . So in this case iMac19,1 Series CPU options."

"Morning Guys,

I kinda used this thread as the catalyst to go ahead and upgrade my base 27-inch 2019 (only bought last week to be fair).

I wasn't convinced that the i9-9900KF or other higher spec processor would work. Its a big lay out for a punt.

So I opted for the i9-9900K. £450 new.

I opted for this processor due to this being an option straight from Apple. Anything googled online only really suggests the board supports 4 options.

I also upgraded the RAM to 64gb but while is was in, installed a 1TB SSD and 128GB PCIe blade (that I had spare which came out of a 2015 MacBook Pro).

I have to say, not the easiest job.

Two key areas that are a headache:

1. refitting the tension spring to the back of the CPU.

2. Refitting the screen (mainly because it was my first attempt).

However, I have to say, the machine fired back up first time, absolutely no issues.

Key point - The fusion drive, for obvious reasons, splits. Again a noob to this, but actually wasn't so hard to fix. I'm an OCD kinda guy and hated having a separate SSD & PCIe drive. I want the OS to run from the blade and the crap loaded onto the SSD.

Easy process.

Boot from your previously cloned externally HDD. Note - the clone on this drive automatically splits into two volumes when it copied my original fusion drive.

Go into recovery mode at boot up. Takes a few minutes to boot.

Run terminal from the utilities menu and the ""diskutil resetFusion"".

Reboot the machine from your external drive and clone back onto your newly built fusion drive. You can rebuild a fusion drive with SSD & PCIe.

Job done.

I have to say, the machine is running well. Geekbench scores are pretty much inline with average scores for this new spec.

Update (05/15/2020)

Key point - The fusion drive, for obvious reasons, splits. Again a noob to this, but actually wasn't so hard to fix. I'm an OCD kinda guy and hated having a separate SSD & PCIe drive. I want the OS to run from the blade and the crap loaded onto the SSD.

Easy process.

Boot from your previously cloned externally HDD. Note - the clone on this drive automatically splits into two volumes when it copied my original fusion drive.

Go into recovery mode at boot up. Takes a few minutes to boot.

Run terminal from the utilities menu and the ""diskutil resetFusion"".

Reboot the machine from your external drive and clone back onto your newly built fusion drive. You can rebuild a fusion drive with SSD & PCIe.

Job done.

I have to say, the machine is running well. Geekbench scores are pretty much inline with average scores for this new spec."

"Confirmed today, I took apart my 2019 iMac base 6 core 8500.

Upgraded to Samsung 970 EVO Plus 1TB - No Issue with the Latest firmware 2B2QEXM7 released on 2019/5/20.

Upgraded to 12TB Seagate EXOS HDD - Have hdd fan speed issue, did not put the OWC sensor. Use Mac Fan Control as alternative solution.

Upgraded Ram Kingston KHX2666C15S4/16G - No Issue.

The CPU is changeable, not soldered - Not upgraded yet, I'm okay with 8500's performance so far. But I'm sure the CPU is upgradeable.

Update (06/24/2019)

Upgrade is fine, but the photos in https://www.instagram.com/p/BzF7bNoIreS/ seems has thermal sensor for the HDD.

BTW, Zach, what is your normal idle fan speed after upgraded to 8TB HDD? Mine idle speed is about 1600-1700rpm, the fan sound is very noticeable. The lowest fan speed is 1200rpm, and the highest fan speed is 2593rpm from the Mac Fan Control settings.

Thanks"

"Hi everyone, I did the core I5 3.0ghz cpu upgrade with Intel I9-9900K and everything went fine.

I only recommend to take out ram Dimm before doing anything, and of course put the ram back inside after iMac reassembling."