FlushMem is a program which allocates and touches as much memory as it can in order to flush the Windows disk cache and page running programs out of physical memory. See this post for the motivation.
Fair warning: most programs don’t handle running out of memory, so don’t be surprised if
flushmem.exe causes running programs to crash, potentially losing your data.
In Cygwin, compile with
g++ -mno-cygwin -Wall -o flushmem flushmem.cpp -lkernel32