Antialiased fonts makes scrolling noticably slower

["paul r" <paul.r.ml@gmail.com>]

Hello,

I'm starting emacs 23.0.60, on gnu/linux
 - under X
 - with free ati graphic drivers (r350 IIRC)
 - 1.7Ghz x86 cpu
 - with option -fn "Dejavu Sans Mono-14"

In a long buffer, if I do
   C-u 1 C-v
, then I do
  C-x z  (holding this z)
to scroll line after line.

Buffer scrolling is slow, letter drawing make them blink, and cpu
peaks at maximum.
Do everybody experience slowness with antialiased fonts ? Is that
inherant to the hard work required to compute antialising, or to a
poor performance in 2D on my box, or something else maybe ?
Of course I do not experience this behaviour at all when antialiasing
desactivated.

Thanks

Paul