2019 iMac RAM

mendozaspeed

macrumors newbie
Original poster
Mar 20, 2019
3
1
I have a 2017 iMac with extra ram, two 16GB stick 2400MHz DDR4. I just purchased the new 2019 iMac and noticed the ram specs are now 2666MHz. Do I really need to buy 2666MHz ram, or can I use the extra ram that I currently have that's 2400MHz?
 

MrSpock75

macrumors member
Apr 10, 2015
70
67
Düsseldorf, Germany
Last edited:

dlewis23

macrumors 6502a
Oct 23, 2007
922
668
You don't have to buy new ram. It will clock the new 2666 MHz ram down to 2400 MHz.
 
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potatis

macrumors 6502a
Dec 9, 2006
806
233
You don't have to buy new ram. It will clock the news 2666 MHz ram down to 2400 MHz.
But he wanted to do the other way around, use the old 2400 MHz modules in a new 2666 MHz machine?
It will not clock up of course, but in my older Mac mini I can use lower spec:ed ram if I remember correctly, and even mix modules. They both clocked down to the lowest capacity of them both. But newer machines might not allow that.
 

AlexJoda

macrumors 6502a
Apr 8, 2015
757
579
Normally the computer gets adjusted to the RAM speed automatically. You won't notice that speed difference in any way. Best is to try it out. You can't damage anything....
 

dlewis23

macrumors 6502a
Oct 23, 2007
922
668
Will it affect performance that much?
Nope. You won't notice a difference at all.

But he wanted to do the other way around, use the old 2400 MHz modules in a new 2666 MHz machine?
It will not clock up of course, but in my older Mac mini I can use lower spec:ed ram if I remember correctly, and even mix modules. They both clocked down to the lowest capacity of them both. But newer machines might not allow that.
He wanted to use the 2400 MHz ram from his 2017 iMac in his new 2019 iMac. The new iMac will down clock the 2666 MHz ram to match the 2400 MHz ram he adds to it. It really has nothing to do with it being a newer machine.
 

dimme

macrumors 68000
Feb 14, 2007
1,571
3,649
SF, CA
I see OWC has ram for the new iMac, is it a better bet that others because that are saying it will work in the 2019 iMac?
 

Black Diesel

macrumors regular
Mar 15, 2011
182
28
So it seems 40GB of RAM is going to be a popular choice with the stock 8GB from apple and purchasing an additional (2) x 16GB sticks. I'm assuming 40GB should be plenty for 4K video editing in FCP or Davinci Resolve?

I think I'll wait a few weeks before ordering my RAM to see if there are any issues with some of the different brands/types.