Problems with X if loading the io and mem as the module

[Andrew Muhametshin]

I am sorry for my English. I am compelled to use the electronic translator.

If the "io" and "mem" load as the module, the Xorg works badly.
For example:
in the mozilla or the firefox to open more than one window, at switching 
from one window in another, it is slowly drawn(appear) contents of a window.

But if to build a kernell with "mem" and "io" options, all works perfectly

FreeBSD 5.3BETTA[with1on6]