In processor architectures that support paging, there are usually one or more TLBs or pagewalk caches to cache address translations. On x86, these translation caches are not coherent with memory accesses that modify the page tables, and need invalidating after a page table entry is modified.
The Windows 9x kernel contains code that modifies a page table entry, then immediately uses it without an invalidation. This causes crashes if the processor strictly follows the instruction set specification and does not provide pagewalk coherence.
. . . → Read More: Windows 9x TLB Invalidation Bug