I have just bought a new Lenovo Ideapad Z580, which came with Windows 8.
I have since, removed that and installed 12.04 on top. Everything works fine. However, after I have to updated all 272 updates using update manager, my machine now takes about 15mins to get to the password/login page. Once I have logged in everything works fine.
I have a before and after bootchart image if that helps (should I save it online e.g. pastebin, or can I attach it here?). It's very odd, in that the slow image has the opening init command taking over 1000 seconds, before the boot process kicks in.
Since having this issue I have tried multiple things to fix it with no success.
Yesterday however, I did spend the entire day updating 5-10 updates at a time, to see if I could find the culprit for the slow boot. After going through all of them, I managed to get everything installed fine! It worked!! Then I went to install Mate on top, and bang, back to 15 minute boot times. Uninstalling Mate, didn't fix this!
I currently have it working because I removed the latest kernel 3.2.0-35, so now have 3.2.0-29.
I did this by doing
sudo apt-get purge linux-image-3.2.0-35-generic sudo update-grub2
However, even though it is working now, I know that if I upgrade anything I will be left with the 15 minute boot times again.
Hopefully someone out there can help.