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?
You don't have to buy new ram. It will clock the news 2666 MHz ram down to 2400 MHz.
Will it affect performance that much?
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.
It’s what I ordered so I hope so!IS this the correct ram for the 27" i9?
Crucial 32GB Kit (16GBx2) DDR4 2666 MT/s (PC4-21300) DR x8 SODIMM 260-Pin Memory - CT2K16G4SFD8266