4K, 2M ("large page"), or 1G ("huge page") on x86-64. A single allocation request can consist of multiple page sizes. From Windows Internal 7th Edt Part 1:

    On Windows 10 version 1607 x64 and Server 2016 systems, large pages may also be mapped with huge pages, which are 1 GB in size. This is done automatically if the allocation size requested is larger than 1 GB, but it does not have to be a multiple of 1 GB. For example, an allocation of 1040 MB would result in using one huge page (1024 MB) plus 8 “normal” large pages (16 MB divided by 2 MB).

Right (on x86-32 and -64, because you can’t have 64KB pages there, though larger page sizes do exist and get used). You still cannot (e.g.) MapViewOfFile() on an address not divisible by 64KB, because Alpha[1]. As far as I understand, Windows is mostly why the docs for the Blink emulator[2] (a companion project of Cosmopolitan libc) tell you any programs under it need to use sysconf(_SC_PAGESIZE) [aka getpagesize() aka getauxval(AT_PAGESZ)] instead of assuming 4KB.

[1] https://devblogs.microsoft.com/oldnewthing/20031008-00/?p=42...

[2] https://github.com/jart/blink/blob/master/README.md#compilin...