Need to write a tool for this that sets/clears the ………… flag in the PE .EXE header.
Officially it is for this:
[Wayback/Archive] IMAGE_FILE_HEADER (winnt.h) – Win32 apps | Microsoft Learn
- IMAGE_FILE_UP_SYSTEM_ONLY
- 0x4000
The file should be run only on a uniprocessor computer.
In practice, this sets the affinity to 1 single CPU core (which is kind of random, and could change each time you start the executable).
This is ideal for code that is known for causing trouble executing on multiple cores, or – more importantly – to disallow core-switching for programs that give best performance when executed on a single core.
Via: [Wayback/Archive] Thread by @0gtweet on Thread Reader App – Did you ever hear about IMAGE_FILE_UP_SYSTEM_ONLY flag in NtHeader->FileHeader->Characteristics of an exe file?
The Wiert Corner - irregular stream of stuff 