We just installed 4x16 gb owc yesterday. Full speed. Did it befor we even turned it on for first time. I did check the sticks to make sure it was all the same brand. Hynix is what I got. Hopefully all is well forever. No need for me to ever get more it’s already overkill for my uses!!
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Memory upgrade troubleshooting in 2020 27-inch iMacs
- Thread starter KrazyKanuck
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Great to hear, are the Ram modules green or blue? What made you pick owc over crucial?
I forget the color already. Think it was blue.
I picked owc cause I’ve heard great things about their support
I was worried for weeks that this wouldn’t work. I had to return my first shipment because the imac box was really wet. I guess reading the forums while waiting made me a wreck haha. All is good with the memory. Now those white line glitches that’s another story for another thread!
2nd and the 4th slots were occupied already. I put the new ones to the 1st and 3rd slots.
You have to put the old ram in slots 1&2 and the new ram in slots 3&4 to get the correct speed. You won't have dual channel however.
Issue is mixed ram... has to be 100% identical in every way to use the 1&3 and 2&4 configuration and get dual channel.
Since the sticks are the same size and spec, he should still maintain dual channel. Sadly only way to confirm is to install Windows and CPU-Z. The only hint one has maintained dual channel in MacOS is Geekbench scores being in the normal range.
Okay, this has fixed my issue. They all run at 2667 MHz now. I thought the sticks should be same on 1&3 and 2&4. Thanks!
Can you do a Geekbench 5 run? That should give you a hint if you have kept dual channel. Looking up the 10500 iMac's, single core should be around 1100 and multi around 5500-6000( with the lower scores being 8 GB of RAM and higher scores having more).
Sure. Here are the results;
SC: 1064
MC: 6075
OpenCL: 36564
Metal: 36985
All seemed normal to me.
So I would say you still have dual channel.
Only way to be sure again is if you install Windows and CPU-Z, but it seems Geekbench takes advantage of dual channel vs single channel hence the lower scores when people with different ram sizes did 4x4x8x8 for example. That would result in losing dual channel( but keep 2667 Mhz speed).
But since you have the same size installed, doing the matched pairs in 1 and 2 and the other in 3 and 4 gets you both full speed and dual channel.
I thought you can tell if it’s utilizing dual channel by looking at system report on MacOS? I remember last year when I updated ram on my 2019 iMac I posted a screenshot of my System report memory tab and members here confirmed to me that it was running in dual channel by the info provided in System Report. Are you saying otherwise? Why would one need to install windows just to confirm if the ram in the iMac is running in Dual Channel Mode at full speed
Nothing in System Report says if the RAM is running in dual or single channel. Most likely they just looked at where the RAM was installed slot wise to say that configuration would result in it running dual channel.
This entire situation is very confusing to say the least, can you or someone please provide a concrete answer as to which ram to purchase precisely in order to get full speed and dual channel support? A 4 x 8 kit from OWC? (Or 4 x 16GB kit for 64 total ram), owc has mixed ram of micron and Hynix but they confirmed to me over the phone that all 4 modules within any given kit will be identical so a 4 x 8gb kit will have 4 identical kits, it becomes an issue if you buy a 2 x kit and another separate 2 x kit because then you can’t guarantee if kit 1 is made by Hynix and whether the other is made Micron at which case the iMac will give you issues with accepting this third party Ram combination..
Why did the majority of people order the crucial Ram for the 2020 iMac? Is it a better quality Ram?
I doubt it. Fixed BOM components are usually the produce for "enterprise" or "industrial" class market segments. Fixed BOM components can also be 5X the price...
It certainly is! I have 2 x 32 GB sticks from Crucial in slots 2 and 4 which are running at 2667 Mhz and according to CPU-Z is in dual channel.
I wouldn't be too concerned with OWC whether it is Micron or Hynix as long as it is the same size sticks( as long as you get two Micron's and two Hynix which you should unless you bought single sticks....). As stated put the Micron ones in 1 and 2 and the Hynix ones in 3 and 4 and you will get dual channel and full speed.
I will repost my rule of thumb again from what people have tested which so far no one has shown info to the contrary.
1. If putting 4 sticks of the same size in, put the matched pairs in the adjacent slots( ie 1 and 2 and 3 and 4).
2. if putting just 2 sticks in the machine, put in either slots 2 and 4 or 1 and 3.
3. Don’t mix different sizes of RAM. But if you must, keeping dual channel is better than restoring full speed. So put the same size sticks in 2 and 4 and the other size in 1 and 3.
Yes, it is confusing, because many of the answers in these forums are only half right.
The following applies only for the 2020 27" iMac:
1. The most sure way to ensure full memory speed (and dual channel) is to have all sticks (whether two or four) 100% identical in every way, including size, brand and part #.
2. However it is possible to mix two sticks of brand A with two sticks of brand B, and still retain full speed AND dual channel (yes, really), provided they are the same size (GB), by putting them in the unusual order: A-A-B-B.
3. It is absolutely not possible to retain both full speed and dual channel if the sticks are not all the same size.
Please don't ask me to explain why. Too time consuming. There are long threads on this that you can read.
Crucial has a stronger following and reputation, but OWC and Timetec also have "Made for MAC" sticks that they guarantee.
Hope this helps
Are the Ram Sticks from OWC better / worse quality than the Ram from crucial or it’s basically all the same and comes down to marketing? I’ll be sure to order a KIT of either 32GB (4x 8) or 64GB (4x16) because the kit contains identical Ram sticks from the same batch as opposed to purchasing two separate kits or individual Ram sticks, the original Apple Ram will be discarded obviously as it’s of no use and I don’t want to mix and match any Ram sticks
I tried a Crucial kit and a Timetec kit. I could tell no difference in performance (benchmarks, RAM transfer speed tests). I think the only difference is opinions and reputation about reliability. All brands have had reported failures (seldom). If they have a lifetime guarantee and good service, which OWC has, I don't think you have anything to worry about. Just make sure they are recommended by OWC as compatible for this particular model of iMac
btw, if you only want 32GB, there is no disadvantage in getting 2x16GB, instead of 4x8GB. It is usually cheaper to do so too.
The advantage to getting 2x16GB, is it leaves 2 slots open so you can increase to 64GB later. Per my item 2 in post #371 above, these do NOT need to be the same brand, but DO need to be the same size.
I confirmed this by putting in 2x16GB of Crucial with 2x16GB Timetec, in order A-A-B-B, and got full ram transfer speed and dual channel.
Thanks for the info, I think I rather install 4 modules than 2 even though installing 2 gives the option of upgrading down the future and might be a bit cheaper. In terms of dual channel, how did you confirm it’s running in dual channel mode?