iBook refresh rates

[Gray Ghost]

I'm trying to cofigure Xorg and it's asking me all these questions about my computer and I've gotten as far as the monitor, It's asking me for the refresh rates for my iBook, my knowlage of this iBook is very limited, it's a graphite ibook, some type of special edition, anyone know where I can find information, such as refresh rates, on this computer?

[x2l2]

i have a white ibook G3 with debian instaled

i have this config on my XF86Config-4 file if can help you....
HorizSync 30-95
VertRefresg 50-150

but on my gnome the refresh rate window say allways 60Hz