[gentoo-user] Xorg-server crashing constantly

[Joseph]

I'm running xorg-server-1.13.4-r1 and XFCE using slim as login
Whenever I start tree applications like: two Firefox and try to open Thunderbird 
or Thunderbird + Firefox and try to open another instance of Firefox xorg-server is crashing and logging me out.

What I mean to say I can start any two of them but not the third one.

xorg-log is not showing anything.  It has been happening on my other machines 
as well.

--
Joseph