My guess: In real world scenarios, there’s overhead such swap space and virtual memory, analogous to a cache miss. A full mark—and-sweep GC would have deal wi

My guess: In real world scenarios, there’s overhead such swap space and virtual memory, analogous to a cache miss. A full mark—and-sweep GC would have deal with this extra overhead. Whereas a generational GC would reduce the amount of a miss because it only considers a subset of objects; and the least likely bit of memory in the disk/slower swap space are the most recently allocated objects.