What kernel are you running (uname -a) ? If does not end on -generic, you shoul reboot and choose the -generic kernel flavour. speedstep-centrino works fine in that kernel. If it's not available in grub:
apt-get install linux-image-generic -- speedstep-centrino module fails to load https://launchpad.net/bugs/66812 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
