2019 iMac 21.5" CPU upgrade - list of compatible CPUs

[sheapuppy]

I purchased this dog back before the pandemic. Mine is the original basic paltry unit with no NVMe slot, a 5400rpm 1TB drive, 8GB RAM, and an Intel i3-8100 CPU. Needless to say, this machine was a disappointment from the beginning. Since then, I upgraded to a 1TB SSD and 32GB RAM.

My last upgrade is the CPU. I was able to find a decent price on an Intel i7-8700K. That said, the TDP on the 8700K is 95W versus the recommended 65W for this iMac.

Has anyone performed a successful CPU upgrade on the 21.5" 2019 iMac? If so, which CPU? I see really good deals on the i5-9700F and i5-9400F which don't have integrated GPUs. That said, this iMac has a Radeon 555X which is not the best in the world but for every day use, it's fine.

Any advice would be helpful.

Thanks in advance....JP

 

[Biggus_Baratheon]

Hey, I have the same model and will be following a similar upgrade path. Just waiting on the last few components to arrive. Did you have much trouble with disassembly for the SSD and RAM?

For the CPU I bought an i7-9700 to match the TDP 65W (currently has an i5). Like you I was wary of going with a K version with a higher TDP.

 

[sheapuppy]

Hey, I have the same model and will be following a similar upgrade path. Just waiting on the last few components to arrive. Did you have much trouble with disassembly for the SSD and RAM?

For the CPU I bought an i7-9700 to match the TDP 65W (currently has an i5). Like you I was wary of going with a K version with a higher TDP.

Give yourself a weekend to work on it. Took me about 4-5 hours total as I was marking every screw to make sure I did it correctly. The hardest part was to take the speaker next to the logic board. You have to wiggle it carefully when taking it out as well as when putting it back in. My advice is once you put it back in place, plug a USB thumb drive to make sure the ports are aligned correctly.

 

[macguru9999]

I just did this upgrade. I had an i3 model that someone gave me that was very slow, actually a cpu issue not hard drive. Of course I was not sure that the cpu was the problem, but i bought an i5 8500 and installed that and changed the ram to 16g of 2666 and the hard drive to a sata 2tb crucial ssd. Its now really good. Speed is fine.
If I had known the motherboard was fine I may have gone with an i7 8700 cpu and 32GB ram, but I was only 50% sure that the i3 cpu installed was really the issue. Also, its a pity that there is no pci ssd slot on the base model, a 2tb M.2 nvme drive would have been an awesome upgrade.

 

[Biggus_Baratheon]

I just did this upgrade. I had an i3 model that someone gave me that was very slow, actually a cpu issue not hard drive. Of course I was not sure that the cpu was the problem, but i bought an i5 8500 and installed that and changed the ram to 16g of 2666 and the hard drive to a sata 2tb crucial ssd. Its now really good. Speed is fine.
If I had known the motherboard was fine I may have gone with an i7 8700 cpu and 32GB ram, but I was only 50% sure that the i3 cpu installed was really the issue. Also, its a pity that there is no pci ssd slot on the base model, a 2tb M.2 nvme drive would have been an awesome upgrade.

If you ever want to be adventurous with it I saw a video once on youtube of someone that soldered the pci ssd connector to the motherboard (as the pads are still there) and they got an nvme drive working through it!

 

[macguru9999]

If you ever want to be adventurous with it I saw a video once on youtube of someone that soldered the pci ssd connector to the motherboard (as the pads are still there) and they got an nvme drive working through it!

Given what a pain these are to take apart I may just wait until I get one with a fusion drive and play with that .... I figure a 1-2 TB nvme blade and a 2-4TB sata ssd , with 32-64 gb ram would be quite useful

 

[jlfriddell]

I am in the exact same situation as you guys. I purchased an 21.5" 2019 i3 back in 2020 for my wife.. The computer stinks and is really..really.. really slow, she has been complaining for several months. I was about to just buy her a new one when i found this thread. I ordered 32 GB RAM and a 1 TB sata SSD and am going to try and fix vs $1400 for new one. I also found a i7 8700 cpu online for good deal. Watching videos online I am confident i can DIY the upgrades mechanically.. But my question is? Is there a lot of software work-upgrades required as well, or is it really as simple as 1) cloning the existing HDD to the new SSD, 2) opening up the imac, 3) installing all the new hardware and simply starting the computer, and all should work as normal??? Assume all the hardware upgrades I ordered are correct (new from OWC).

Any feed back or advice would be well received, Thanks...

 

[jlfriddell]

I just did this upgrade. I had an i3 model that someone gave me that was very slow, actually a cpu issue not hard drive. Of course I was not sure that the cpu was the problem, but i bought an i5 8500 and installed that and changed the ram to 16g of 2666 and the hard drive to a sata 2tb crucial ssd. Its now really good. Speed is fine.
If I had known the motherboard was fine I may have gone with an i7 8700 cpu and 32GB ram, but I was only 50% sure that the i3 cpu installed was really the issue. Also, its a pity that there is no pci ssd slot on the base model, a 2tb M.2 nvme drive would have been an awesome upgrade.

I am in the exact same situation as you guys. I purchased an 21.5" 2019 i3 back in 2020 for my wife.. The computer stinks and is really..really.. really slow, she has been complaining for several months. I was about to just buy her a new one when i found this thread. I ordered 32 GB RAM and a 1 TB sata SSD and am going to try and fix vs $1400 for new one. I also found a i7 8700 cpu online for good deal. Watching videos online I am confident i can DIY the upgrades mechanically.. But my question is? Is there a lot of software work-upgrades required as well, or is it really as simple as 1) cloning the existing HDD to the new SSD, 2) opening up the imac, 3) installing all the new hardware and simply starting the computer, and all should work as normal??? Assume all the hardware upgrades I ordered are correct (new from OWC).

Any feed back or advice would be well received, Thanks...

 

[macguru9999]

since all the same software will run with those hardware changes you can simply clone across if you wish. I predict it will be fast enough for her just changing the hd for a sata ssd without pulling the mobo to do the ram and cpu. But if you are handy and like extra work it should make it even better. but i would try just the ssd change first, tape the screen on temporarily and try that.

 

[jlfriddell]

Great thanks for the advice..

 

[macguru9999]

Great thanks for the advice..

no worries, you may have read my post earlier where my slowdown was a cpu malfunction, afaik, so i had to change that i3 and used an i5. but i think that kind of problem is very rare, your cpu is probably ok

 

[Biggus_Baratheon]

I completed the CPU, RAM, and SSDs yesterday and everything went well! I found removing and resticking the screen by far the most stressful part. And removing all the gunk from the edges.
Once it was opened up replacing everything was pretty straight forward, few awkward cables here and there. The computer is now lightning fast compared to its previous performance.

I now have a 32GB Apple proprietary NVME drive lying around with no cost effective way to make it into an external drive....Classic Apple using non-standard connectors.

 

[macguru9999]

I completed the CPU, RAM, and SSDs yesterday and everything went well! I found removing and resticking the screen by far the most stressful part. And removing all the gunk from the edges.
Once it was opened up replacing everything was pretty straight forward, few awkward cables here and there. The computer is now lightning fast compared to its previous performance.

I now have a 32GB Apple proprietary NVME drive lying around with no cost effective way to make it into an external drive....Classic Apple using non-standard connectors.

what ssd did you use in the pcie slot ?

 

[Biggus_Baratheon]

what ssd did you use in the pcie slot ?

I used a 1TB Western Digital SN550 with this adapter (‎ELIATER ‎B097G2CR6B);

M.2 NVME SSD Convert Adapter for Upgraded MacBook Air Pro Retina Mid 2013-2017, NVME/AHCI SSD Upgraded Kit for A1465 A1466 A1398 A1502

M.2 NVME SSD Convert Adapter for Upgraded MacBook Air Pro Retina Mid 2013-2017, NVME/AHCI SSD Upgraded Kit for A1465 A1466 A1398 A1502

www.amazon.ca

The adapter was recommended somewhere else on this forum.

 

[Bor1s]

Hello!
Did you have some problems with the upgrade from i3 8100 to i7 8700? I tried to upgrade the same base iMac 21.5” 2019 without pci-e slot with more RAM, SSD and better CPU, but the only part that didn’t work was the 8700. The system is not booting at all with the new CPU and that doesn’t make sense! Apple has the base 21.5” with i7 8700 cpu configuration and I don’t think they have a different logic board for every single configuration! What’s the catch ?

 

[macguru9999]

Hello!
Did you have some problems with the upgrade from i3 8100 to i7 8700? I tried to upgrade the same base iMac 21.5” 2019 without pci-e slot with more RAM, SSD and better CPU, but the only part that didn’t work was the 8700. The system is not booting at all with the new CPU and that doesn’t make sense! Apple has the base 21.5” with i7 8700 cpu configuration and I don’t think they have a different logic board for every single configuration! What’s the catch ?

dunno, I used a Core i5 (8500) in my 2019. worked like a charm. The OP used the wrong i7 chip. ("K") All 3 use the same logic board.

 

[Bor1s]

dunno, I used a Core i5 (8500) in my 2019. worked like a charm. The OP used the wrong i7 chip. ("K") All 3 use the same logic board.

Hi! Thank you for your reply!
So you also have the same iMac 2019 21.5 base with i3 8100 CPU which you upgraded to i5 8500? You too don’t have pci-e slot for blade ssd on your logic board?
Do you think it’s a problem of micro coding and that all the i7 CPUs are not compatibile with our systems?
Maybe with the i5 base cpu, another iMac 21.5 2019 would’ve been compatible with even an i9.
I’ll try with your same cpu, hope it’ll work!

 

[macguru9999]

Hi! Thank you for your reply!
So you also have the same iMac 2019 21.5 base with i3 8100 CPU which you upgraded to i5 8500? You too don’t have pci-e slot for blade ssd on your logic board?
Do you think it’s a problem of micro coding and that all the i7 CPUs are not compatibile with our systems?
Maybe with the i5 base cpu, another iMac 21.5 2019 would’ve been compatible with even an i9.
I’ll try with your same cpu, hope it’ll work!

If you use the Core i5 (8500) 3.0ghz, or Core i7 (8700) 3.2ghz ("Coffee Lake") it will work. As I said above the OP used the wrong chip, the 8700K will not work AFAIK. I only changed mine because the i3 cpu was failing, and somehow locked at 0.8ghz instead of 3.6ghz. Swapping the cpu fixed the problem. I also put a sata ssd and more ram in mine of course but sadly it had no slot for a pcie ssd. But its good.

I am not sure if its worth the trouble of changing out a working cpu, however. I used a working i3 model recently and its fine for everyday things... but if you are doing more challenging stuff I would try the i7, just get the correct model.

 

[sheapuppy]

If you use the Core i5 (8500) 3.0ghz, or Core i7 (8700) 3.2ghz ("Coffee Lake") it will work. As I said above the OP used the wrong chip, the 8700K will not work AFAIK. I only changed mine because the i3 cpu was failing, and somehow locked at 0.8ghz instead of 3.6ghz. Swapping the cpu fixed the problem. I also put a sata ssd and more ram in mine of course but sadly it had no slot for a pcie ssd. But its good.

I am not sure if its worth the trouble of changing out a working cpu, however. I used a working i3 model recently and its fine for everyday things... but if you are doing more challenging stuff I would try the i7, just get the correct model.

I can confirm that the i7-8700K CPU will boot BUT unless the heatsink is upgraded it will shut down within a few minutes.

 

[macguru9999]

I can confirm that the i7-8700K CPU will boot BUT unless the heatsink is upgraded it will shut down within a few minutes.

Its an imac , its crazy to try and change the original design like that. What you want is 100% reliability. Most of the speed improvement comes from fitting an ssd anyways, just a sata one.

 

[Bor1s]

I can confirm that the i7-8700K CPU will boot BUT unless the heatsink is upgraded it will shut down within a few minutes.

Hi !
Just to be sure:
You can confirm that the i7-8700 will work with the iMac 21.5” 2019 A2116 logic board base model (with i3-8100) without pci-e slot?
I have that model, I tried with the i7-9700 and the iMac can boot but won’t load the OS.

The next CPU that I tried was exactly the i7-8700, but the mac didn’t boot at all!
On the logic board there’re 5 leds for status and error identification, when the system is turned on only the #1 and #2 are on. No boot sound, no video signal, only the cpu fan going faster and faster.

Then when I switched with the original i3 8100 everything was good.
I don’t understand if the i7-8700 was faulty or there’s something missing from the bios of the logic board.

 

[sheapuppy]

Hi !
Just to be sure:
You can confirm that the i7-8700 will work with the iMac 21.5” 2019 A2116 logic board base model (with i3-8100) without pci-e slot?
I have that model, I tried with the i7-9700 and the iMac can boot but won’t load the OS.

The next CPU that I tried was exactly the i7-8700, but the mac didn’t boot at all!
On the logic board there’re 5 leds for status and error identification, when the system is turned on only the #1 and #2 are on. No boot sound, no video signal, only the cpu fan going faster and faster.

Then when I switched with the original i3 8100 everything was good.
I don’t understand if the i7-8700 was faulty or there’s something missing from the bios of the logic board.

I have the same model - no PCIe slot. Also just to be clear I installed the K model of the i7-8700 CPU. It sounds like the CPU you had (i7-9700) is not supported for some reason 🤔

 

[Bor1s]

Thank you for your support!
So practically, there’s no proof of CPU i7-8700 (without K) working with the base logic board of the iMac that we have ?
At the end, which CPU you have now on your iMac, @sheapuppy?

 

[sheapuppy]

Thank you for your support!
So practically, there’s no proof of CPU i7-8700 (without K) working with the base logic board of the iMac that we have ?
At the end, which CPU you have now on your iMac, @sheapuppy?

I ended up installing an i5-8500 CPU. I sold the i7-8700K because I couldn't justify making the thermal changes to support that CPU in this machine.

 

[agala68]

Hey, I have the same model and will be following a similar upgrade path. Just waiting on the last few components to arrive. Did you have much trouble with disassembly for the SSD and RAM?

For the CPU I bought an i7-9700 to match the TDP 65W (currently has an i5). Like you I was wary of going with a K version with a higher TDP.

Hi,
what RAM speed you have used to upgrade the CPU from i3 to i5/i7?