X + mouse + resolution = splat!

[Neskia Moo]

Alright, hello all you BSDer people.
I'm a newbie, flame me, love me, cherish me, hate me..

I just installed FreeBSD 6.2 and was configuring X
well, xorg -configure or the like commands didnt work
ended up having to go with xorgconfig

I then had a problem that didnt really make sense.
if the resolution is 640x480, everything works normally.
If i use a higher resolution (which i want to , to be able to multitask
reasonably, or even just use a browser to fit the screen) the mouse fails,
it shoots up to the top right side of the screen and stays there.. some
times opening the menu when i try to move it.

this makes no sense to me, because i cant see how the video drivers and
mouse drivers would effect each other.. anyone else ever heard of a problem
like this?