True, but having every structure aligned to exactly the same offset into each page is extremely unlikely. Given a page size of 4KB then a whole bunch of 32 byte

True, but having every structure aligned to exactly the same offset into each page is extremely unlikely. Given a page size of 4KB then a whole bunch of 32 byte structures aligned in such a way would represent a huge waste of memory. No sane allocator will allocate things like this. If your structures happen to be very close to the system's page size it could easily happen, then you'd need to avoid this yourself with your own incremental allocator (or other tricks). Definitely agree with your last point, I've seen lots of code (in commercial applications) where people are optimising completely the wrong thing.