MK> And when the scrolling is going on the other programs 
 MK> gets no or close to no cpu at all.

Your problem is caused by hardware;  your video card (or driver) is too slow. 
 Scrolling a text window requires a LOT of video memory to be moved around.   Try:

       1) A faster local-bus video card,  with a video driver that
          can take advantage of the firmware scrolling (some cards support
          a hardware cursor too)
       2) A lower resolution (I bet "dir /s" will fly by at 640x480x16,
          because less video memory is involved)
       3) Run the program in a full screen session (where the whole screen
          is typically 4k of memory,  vs 100's of KB in a window).

 MK> this effect.  I don't have the same problem when 
 MK> scrolling for example an E.EXE window.

That's because E is not a "free running scroll" like "dir /s".

--- Maximus/2 3.00