Could you test this ?

FPS Max=2480 aprox
FPS Min=1430 aprox
Pentium core duo extreme 3GHz. Nvidia 6800. XP SP2

While progress the scroll the FPS is decreased.
If the scroll is plus large the FPS are unusable.
Probabily leak in gestion of resources: Excesive paints, memory, etc.

Bye,
Paposo