Petr,
I have reworked the demo to reduce the CPU footprint,
while keeping the nominal frame rate of the original GIF animation, aka
12 FPS.
Here are the result shown under task manager:-
Windows XP SP2 running on Dual Core 1,
CPU = 33 to 34 %, the nominal FPS being respected.
-
Windows VISTA 64-bit running on Dual Core 2 Duo,
CPU = 24 to 33 %, the nominal FPS being respected.
On the same computer in full screen mode (HD 1920 x 1080), CPU = 31 to 34, still running at the GIF nominal 12 FPS rate.
And for those that are not aware of it, the maximum FPS you can get
on VISTA / W7 while running
in cooperative mode is 64 FPS, everything else is false allegation.
Working in cooperative mode, means that you can still run the other applications

Note: The EXE file has been cleaned up, with zXref.
...