Thanks, Tony, I probably would've missed this.
My best guess would be the video drivers - ATI's Linux support isn't the greatest, and things are usually much smoother with nVidia chipsets.
That being said, you can make sure you're running real, recent drivers using a package called "Envy-NG". From a terminal:
Code:
sudo apt-get install envyng-core envyng-gtk
Once that's installed, run "sudo envyng -g" in a terminal - it should be pretty self-explanatory to install the ATI drivers. Like I said, ATI video doesn't work as easily as nVidia, but since you're on a laptop, your choices are limited.
You can read more about EnvyNG
here.
Good luck!