Reducing power usage.

I am trying to get the power usage down, at the moment I see (Install xubuntu) a lot of wakeups on the cpu.
It looks like the kernel is migrating a job from one virtual cpu to the other (the hyper threading one (or do they call it differently now?)) Problem also discussed here: http://www.nabble.com/Rescheduling-inte ... 09292.html.

If I look at my single core thinkpad, I can get this down to +-15 wakes up/sec. I am kind of amazed that my full size laptop with 1400x1050 screen, 7200rpm disk manages to idle at 10.8-11.5W while this lot smaller laptop uses only 1-1.5 W less.

Any tips?

 

I realise I posted this in the wrong section (I should not be posting late at night) maybe some mod can move it.

Most of the Rescheduling interrupts seems be be caused by xfwm4's window manager. Turning that of reduced the amount of wakeups caused by the rescheduling int. by a factor 10.
I still have the issue of allot of wakeups coming from the usb system.. (uhci_hcd:usb3 and ehci_irq).

(removing the usb and wifi subsystem reduces the wakeups to 14-28times/sec (still to much0 and drops the power usage to 8.1W)

edit: Starting the system with acpi=noirq seems to reduce the wakeups caused bye the Rescheduling interrupts)