About QueryPerformanceCounter

I Use QueryPerformanceCounter in UE4 Editor,It is accurate,But After the project is packaged,It becomes inaccurate,AnyOne know why?

Hi, I was wondering how you were able to implement QueryPerfomanceCounter. I have been getting some errors when including “Windows.h” so I changed it to “Windows/WindowsSystemIncludes.h”. when I do this, LARGE_INTEGER and QueryPerformanceCounter throw errors.

error 32065: ‘LARGE_INTEGER’: undeclared identifier
error C3861: ‘QueryPerformanceCounter’: identifier not found

Any info would greatly help, thanks!