Why is Ubuntu so power-inefficient?

Question

Possible Duplicate:
Battery drain on ubuntu is fast

I'm currently getting 7–8 hours of battery life whilst using Windows, but I only get about 3 hours in Ubuntu? Why the big gap?

Some theories of mine:

1. Specialised/optimised drivers in Windows
2. More resource usage in Ubuntu
3. Lack of effective power-saving feature in Ubuntu, vs. Windows, which specifically tries to reduce battery usage when on battery power
4. Dell has a conspiracy with Microsoft.

Seriously, though. I have a 9-cell battery; I should be getting much better life, right?

Any way to solve this problem?

Answer 1

There is a kernel bug causing this, but it's easy to fix:

In terminal:

gksudo gedit /etc/default/grub

Find the line that looks like this:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

And make it look like this:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash pcie_aspm=force"

Finally, in terminal:

sudo update-grub