I have HP ProBook 4530s. In Windows 7 after installing all HP drivers the 6-Cell battery works perfectly for 2+ hours but in Ubuntu 11.10 and now in 12.04 the battery time is not sufficient. It works hardly for 1 or 1.5 hours only. I have installed ATI's Linux Driver for the RADEON card.
I have noticed that in Windows only 4 processor core are active most of the time and remaining are put in off-line mode until required. However in Ubuntu all 8 processors cores remain active.
Powertop shows a battery discharge of 25 W up to 28 W.
How can I tune-up the power management especially make unnecessary active processor off-line?