Question DDR5 Ram into a DDR4 Motherboard?

[ju1c3]

This is all a hypothetical, as I'm not dumb enough to do this, but I'm curious what will happen if I put DDR5 ram into a Motherboard that only supports up to DDR4?

 

[DSzymborski]

The same thing that happens if you shove a Super Nintendo cartridge into a Sega Genesis; it doesn't fit and you break one thing or the other. The RAM sticks are physically incompatible and even if they were not, it still wouldn't work.

 

[drivinfast247]

It's a secret. Something magical happens.

You can't, it's keyed different. Won't even install.