xawtv & refresh rate

[Wiesław Kierbedź <sprawki@xxxxx>]

I see that after fullscreen toggle command xawtv leave low refresh rate 
(60 Hz).
Settings are:
.xawtv
[global]
fullscreen = 640 x 480
ratio = 4:3.

and default (max) X resolution "1280x1024" starts with 75 Hz.

Video driver nvidia 4091 and XFree86 4.2.99.903.
Any suggestion?