The allocator
What a heap allocation costs in Go once escape analysis has decided you are having one — size classes, the routines the compiler picks, and where the cost stops tracking the number of bytes.
1 part
The 30% is 46%, and it stops dead at 80 bytes
Go 1.27's size-specialised allocation is worth up to 46% on the pointer-containing path, not the 30% announced — and from 96 bytes up it is worth nothing.