finally discovered that  emacs -xrm Emacs.fontBackend:gdi   makes scrolling much faster.


2013/6/28 Eli Zaretskii <eliz@gnu.org>
> Date: Fri, 28 Jun 2013 01:28:53 -0500
> From: Mario Valencia <mariovalspi@gmail.com>
> Cc: 14721@debbugs.gnu.org
>
> Well I guess that's it then, there's no way to fix it. :(

Try a faster machine.