iMac Memory Upgrade Bonk

[petercw2]

I've installed 3rd party memory into several iMacs without a single issue, until yesterday.

A friend has a new 2020 iMac i9, and we got two 16g sticks from OWC.
Opened the door, added them in between the two existing 4G sticks and when all back together - zero power. Like it's unplugged.
Tried reordering the sticks, still nothing. Only when I removed the two OWC sticks and put the two OEM back in their two original positions, did the iMac come back to life.

OWC tech service has not responded to any calls, chat or emails.

Anyone here have any suggestions? Thanks in advance for any guidance.

 

[pugxiwawa]

I actually had the same issue on the brand new 2020 iMac i5. Seems memory socket is more sensentivie on this model. I put in 2x16GB Crucial ram in addition to the original 2x4GB Apple ram and the computer would power on but no screen. I tested a few combination and ended up having to remove one of the original 4GB ram. I know the 2x16GB is good because I was using them in my 2020 Mac Mini, so this really puzzles me. But in your case maybe the OWC sticks are bad, unless you have another Mac to test out. Anyway, just want to give some feedback that I think this new model is definitely more sensitive to ram sticks. Good luck.

 

[petercw2]

thank you and good to know this is not unquie. Ironically just now, OWC, after 24 hours of attempting to get them, finally connected via chat - but the guidance wasn't very helpful. They claim the OEM and OWC chips should be able to "go in any order", and then suggested I 1) clean the contact pins with alcohol and 2) attempt SMC and PRAM resets.

 

[glenthompson]

Had similar problems on my wife's 2017 iMac with crashes and not booting. We had added 32gb of OWC ram to the factory 8gb. Finally removed the Apple ram and ran with just the OWC ram and zero issues since. Seems that the Apple ram doesn't play well with 3rd party ram on some machines. 32gb of ram on a fully functional machine is far better than 40gb on a flakey one.

 

[wilberforce]

Opened the door, added them in between the two existing 4G sticks and when all back together - zero power. Like it's unplugged.

When RAM is changed on the 2020 iMac, it can take an additional 30 seconds to boot, during which time it appears completely unresponsive with a black screen. Not sure if you know this and waited the extra time. If you don't wait long enough and push the power button again, you have simply turned it off, and then it gets confusing whether it is on or off.

 

[petercw2]

After giving them all the details about this specific model iMac (20,1) they now tell me it requires that all sticks match in size and brand. weird.

 

[Fishrrman]

OP:

Have you tried using the OWC RAM only, leaving the Apple-factory RAM OUT...?

Will it boot that way?
(give it about 60 seconds after you press the power on button to respond).

If it does...
I recommend your friend run that way, and in the meantime put the factory RAM in a safe place.
It might be necessary to re-install it in the future, so that's why I'd save it (instead of selling it or tossing it out).

If the OWC RAM won't run even "by itself", time to send it back and try something else.

 

[1k9]

Try putting the ram in pairs instead of the normal every other slot.
apple
apple
Owc
Owc

 

[anthony13]

Assuming you get this configuration to work, be aware that should you mix both types, you're going to reduce your Ram speed to 2133. This model is very sensitive to RAM and configuration of any ram. There's a pretty extensive thread on this somewhere in the forums, I'll try to find it in my history.

But the long and short of it if I remember correctly is that if you want to maintain Dual Channel, and the top ram speed, you need to use only chips with the same amount of RAM (for example 4 16GB chips) and if they are different brands, you need to pair them in slots 1&2 and 3&4. Because you have different capacities, using the apple RAM is going to drop your RAM speed, which some would argue is more valuable then the additional 8GB of RAM you get by keeping them.