"Just" 1600x1200...

Anyway, since you say that there is no slowdown after the first time, just show the panel briefly when starting the game. You can set a lower layer flag and hide it behind a titlescreen or even the A4 / A5 logo, just to get it loaded. This will take a second, but since it is during the "loading" phase, it doesn't matter anyway. From then on, it should work.

Can't think of a better solution...

Gnometech