Ram underclocking on iMac?

[amadii]

I have 2 sticks of 8 gigs of ram at 2400mhz with an imac coming with 8 gb at 2667, if the 2 sticks were to be added would the mac underclock the 2667 one or would it not boot?
 

[TetraSky]

Try it and tell us what happens.

 

Apple says you need to use 2667 RAM. 

https://support.apple.com/en-us/HT201191#27inch2020

 

and their drones repeat it as gospel and talk as if you're going to break everything if you do it

https://discussions.apple.com/thread/251751930

 

But coming from a DIY PC building perspective, it should work and it should underclock. Whether or not Apple plays nice, that's a different story.