Where would you buy upgrade RAM for a 2020 iMac?

[MR_Boogy]

Here in the UK, Crucial and Kingston are the two names I know well for RAM, but I am seeing fairly sizeable price differences between them. As long as it's 2666MHz SODIMM from someone reputable should I care?

I've already seen on here notes about pairing DIMMs by size. Can I check - are single DIMMs allowed e.g. can I add a single 32Gb or is that a bad plan?

 

[PBG4 Dude]

2020 iMac needs RAM in pairs. I have 2x32GB Crucial in mine, which I bought directly from them. As you say, any SODIMM matching the 2020’s requirements should be usable. There is a thread here somewhere that catalogued all the different RAM sticks that were tried, as well as other gotchas that were found.

 

[MR_Boogy]

So for instance I could buy 2x16Gb now, to add to the installed 2x4Gb (giving 40Gb).
Then in a year or two buy 2x16 or 2x32 to replace the 4Gbs giving 64 or 96. The new iMacs will go u to 128 which is nice

 

[PBG4 Dude]

So for instance I could buy 2x16Gb now, to add to the installed 2x4Gb (giving 40Gb).
Then in a year or two buy 2x16 or 2x32 to replace the 4Gbs giving 64 or 96. The new iMacs will go u to 128 which is nice

You don‘t want to mix RAM sizes in 2020 iMacs. You won’t get the benefit of dual channel if you do that. That was a finding in the huge RAM thread I mentioned earlier. I’ll see if I can dig up a link.

Edit:

https://forums.macrumors.com/threads/memory-upgrade-troubleshooting-in-2020-27-inch-imacs.2249254/

 

[MR_Boogy]

I'd seen a similar thread @PBG4 Dude where there was discussion about 2666 single channel, 2133 dual channel, which order you put the pairs in, etc. As you say the one you link is a monster (22 pages?) did anyone ever write a canonical summary what you can/cannot do or do I need to trawl the whole shebang?

 

[wilberforce]

I have been following and contributing to the 2020 iMac RAM threads for a while, and if you want to keep it simple:

1. Yes, as long as it meets the Apple RAM spec, any mfr will (theoretically) do:

2. Crucial has the best reputation, but others will do just as fine.
3. Most important - buy a brand that has free returns and lifetime free replacement warranty from within your country. Occasionally RAM is faulty, causes crashes.
4. Some have had issues with 4 sticks of OWC RAM, although OWC usually has good reputation.
5. Always install matching pairs. First pair in slots 2 and 4, second pair (if used) in slots 1 and 3.
6. For 2020 iMac, all sticks should be same size. Do not mix with the original 8GB Apple RAM.
7. When you change RAM, allow an extra 30 seconds for the machine to boot (only a black screen shows)

Hope this helps