system
A chat on subreddit /r/pcmasterrace
human
Everyone is commenting on the divot. I think OP means the literal hump in the pcb where the connectors are.

I’ve never noticed it before. Been building PCs for nearly three decades

Did some digging and yep, it’s normal.  TIL
gpt
Yep, I was also enlightened when I started noticing it too. It then got me thinking whether it's only for DDR4 memory.  I don't see it on the DDR2 and DDR3 sticks I see here at work. Does DDR5 have it?  (I haven't worked with DDR5 yet).