2020 27" iMac wont turn on after installing RAM

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Level 1

41 points

2020 27" iMac wont turn on after installing RAM

I just got my 2020 27" iMac with 8gb (2x4gb modules.)

When I got it I moved one 4gb module to slot one. Then installed 2 new 32gb modules in slots 3 and 4. So, basically....

Slot 1 - 4gb original module
Slot 2 - 4gb original module
Slot 3 - new 32gb module
Slot 4 - new 32gb module

The ram I purchased was "Samsung 32GB DDR4 2666MHz RAM Memory Module for Laptop Computers (260 Pin SODIMM, 1.2V) M471A4G43MB1"..... https://www.amazon.com/gp/product/B07N124XDS/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I know it's fully compatible.

I turned on the Mac and NOTHING. No beeping, no booting, no apple, nothing.

I took the Samsung ram out and it boots up.

Then to test if one stick was bad, one at a time, I only added ONE new 32gb ram stick. It wouldn't boot up at all when the Samsung ram is in there.

Any ideas? I doubt that BOTH of my brand new ram sticks were bad. Please help!

(In the meantime, I also order OWC ram so hopefully this will work better.)

iMac Line (2012 and Later)

Posted on Aug 20, 2020 8:52 AM

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Answer 1

Top-ranking reply

BDAqua

Level 10

245,303 points

Aug 21, 2020 11:12 AM in response to WebDevGuy

Aha,from that link...

I put two 32 gb modules (total 64 gb) in my new 2019 iMac 27. Initially I installed it with the original eight gb from Apple and the computer would not power up at all. I had to remove the Apple RAM and install the Samsung memory only and it works fine So, apparently there are some conflicts with mixing the two. They work fine when they are installed alone. However, I have 64 gb in two slots and still have two slots open to add more if I wanted t

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Answer 2

den.thed

Level 10

82,474 points

Aug 21, 2020 8:45 AM in response to WebDevGuy

Sadly, you failed to heed multiple warnings from us back on Aug. 10th and 11th.

see > Installing RAM (2x32gb, 2x4gb) in 2020 27… - Apple Community

Return that RAM, it is for a PC and purchase RAM that is made for, tested and compatible with your iMac.

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Answer 3

Aug 20, 2020 10:46 AM in response to WebDevGuy

Is all RAM running at the same speed? I think they need to.

You can also try removing the 2 x 4GB RAMs so that all RAM is definitely running at the same speed. You'll lose 8GB of RAM but still have 64GB.

All that said, are you sure your Mac can handle that much RAM?

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Answer 4

den.thed

Level 10

82,474 points

Aug 20, 2020 11:15 AM in response to WebDevGuy

Put the factory modules back in the original slots and test. Then install the new modules in empty slots and test.

If that doesn’t work, try the 2 new modules in slots where the original modules were.

If that doesn’t work, then return the Samsung modules and purchase modules from either OWC or Crucial.

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Answer 5

WebDevGuy Author

Level 1

41 points

Aug 20, 2020 3:57 PM in response to Old Toad

It's hard to believe that BOTH ram modules I purchased were bad. They were high rated, compatible, and new. So, that's why I' confused. Plus usually macs will BEEP at you if the ram is bad right? Not refuse to turn on.

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Answer 6

timmac49

Level 1

4 points

Sep 14, 2020 12:39 PM in response to WebDevGuy

I bought 4 16 gig ram chips from OWC. When I filled all slots the Mac would not turn on. If I just populate slots 2 & 4 everything is fine with either set of OWC chips or the original chips/ Any memory put in slots 1&3 casues the computer to not turn on. I'm off the the Apple store soon, as I think slots 1&3 are toast.

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Answer 7

Old Toad

Level 10

210,597 points

Sep 14, 2020 1:26 PM in response to timmac49

I think slots 1&3 are toast.

It certainly sounds like it. I'd put the two Apple modules back in when you take the unit in. You can take a couple of the OWC modules in a bag but start with the Apple sticks.

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