are dynamic windows really 60X slower than old windows?!

["William D. Gooch" <ai.gooch@MCC.COM>]

    I am not interested in mouse-sensitivity here. I am using dynamic windows only for the
    ability to scroll through a virtual window bigger than the actual window size.
    But I will sacrifice this ability for speed, if necessary.

Not necessary, but neither is the use of DW in this case.  I suggest you
consider using the tv:bitmap flavor to create a hidden "canvas" big
enough for all your drawing, and bitblt from it onto the foreground
window as appropriate.  I have had good success with this technique in
building smoothe-scrolling windows that handle graphics much faster than
dynamic windows, and slightly faster in most cases than the old-style
tv: windows.  I can give you more details (and perhaps share some code)
if you're interested.