I know this topic has been covered a million times, but I’m having trouble getting an answer to act on. My new 2020 27” i5 iMac came with 2x4 gigs or RAM. My IT department jammed in a single 32gb chip as an upgrade, despite me asking for a matched pair upgrade. I think this combination is slowing down my memory speeds. I am wondering if I should pull out the 2 x4 pair and run a single 32gb DIMM, or just continue with 3 DIMMs totaling 40 GB.
iMac 27″, macOS 11.6
Phil is correct, however your support team really should return the single 32 GB DIMM and buy 2x 16GB DIMMs from either Crucial.com or Macsales.com. At least then you have matched RAM.
While the speed might in fact be slower, it won't be anything you can actually perceive when running the machine normally unless you do really RAM intensive tasks or have a way to actually compare the before and after.
It's always better to have more RAM than less but faster.
I wouldn't not worry too much about the unpaired RAM stick.
Give the following a try:
The speeds showing are the actual speeds, please run your own report and look at it's speeds.
I was hoping you’d respond, rkaufman. I think a common next question is… are the speeds shown a calculated/detected measurement of RAM performance, or just another posted label like size and type. Have you ever had a 2667 DIMM installed that showed a lower speed in these screens?
Click on About this Mac which is under the symbol in the upper left of the display.
Click Overview tab and the click the System Report.
Look in the report under memory and it will show the RAM that is installed speed.
Below is the report on my 2020 27" iMac, please pay close attention to the layout and speed of the RAM.
RAM Mixing in 2020 iMac
