whats the reason for nonpaged memory?
why windows implement it?

the only diffrence is that it cant be swapped out.

when cpu access memory that is swapped out, it will experience page fault.
page fault handler will copy page to memory and resume execution.

why this is wrong? why when running on high IRQL i must use nonpaged memory?
page fault is exception and it cant ba masked out... so whats the problem in using only paged memory?

CPU sometimes does quite complex accesses to memory internally, eg. memory map, or reading control structure during virtualization.

Also, google "DMA"

in not asking about cpu but about windows internal function reventing me to page fault in nonpaged memory.