Same problem happened with me.
My PC Configuration
Ubuntu 12.10 64 bit
Processor : Intel i3 3.07GHz
Ram : 2GB
Onboard Graphics
No compiz installed\
------
It freezes when I start firefox and google chrome simultaneously.
Also appeared when any development editor like netbeans and rhythmbox running simultaneously
Same problem happened with me.
My PC Configuration
Ubuntu 12.10 64 bit
Processor : Intel i3 3.07GHz
Ram : 2GB
Onboard Graphics
No compiz installed\
------
It freezes when I start firefox and google chrome simultaneously.
Also appeared when any development editor like netbeans and rhythmbox running simultaneously