2019 27" Ram question

[macguru9999]

I note the 2019 imac 27 requires 2666mhz pc4 ram. question:
What happens if you put apple ram from the 2017 model (pc4 2400mhz) in the 2019 imac ?
Does it work ? at 2400 ? does the memory controller sort this out or does the machine become crashy ?

cheers

 

[MacManiac76]

It will work fine, just at the slower 2400 MHz speed for all installed RAM.

 

[macguru9999]

Yes thanks that’s what happens