I run a graphical application, coded in MS Visual C++ 6.0 using MFC.
Occasionally the application seems to generate a problematically high workload
for the CPU and as a result, of course, the program lags. I found a strange way
to solve this problem temporarily, “almost” change the screen resolution.

When accessing Windows XPs change screen resolution dialogue (not accepting
the new resolution but merely previewing the new setting and cancel the
dialogue) my CPU workload is dramatically reduced, from about 50% to 7-10%.
Any suggestions on how this works? How Windows/MFC/VC++ handle screen
resolution changes (memories flushed etc.)?