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Hello,
Sure there are a lot of people using Ubuntu that your laptop when running hot and drain the battery faster than Windows, although the effects were turned off and not run anything. While overheating rarely happens on the desktop. Many people only make guesses as in driver, at chip, in VGA ... or in Ubuntu without knowing the real cause of the problem. Since then made statements that Ubuntu is always hot and the battery power than Windows when running on a laptop.
This statement may be true for notebook / netbook Windows preinstalled at the factory.
This statement wrong notebook / netbook at the factory with no Windows or Linux preinstalled.
Because most laptops on the market (especially expensive high-end line) M $ should be taxed this phenomenon occurs.
Why the world?
The operating system controls the operation of the power consumption of the device through an interface called ACPI (Advanced Configuration and Power Interface). ACPI BIOS is installed in the computer, its control functions such as regulating the voltage and frequency of CPU, fan speed, HDD temperature, state power consumption of peripherals such as monitors, Ethernet, Wifi, ... Bluetooth ACPI also defines the description interface between the operating system and hardware firmware. BIOS is capable of detecting the type of operating system is running, thereby providing the appropriate description.
The laptop is often not M $ tax official support any operating system other than Windows. BIOS only provides full ACPI description and correct the operating system on Windows. If Linux is installed, BIOS will not provide a full description ACPI, even deliberately falsified (âm mưu một thời của M$ – Bill Gates on Making ACPI Not Work with Linux). That led to Linux is not controlled state power consumption of the device correctly, causing overheating problems, battery power, not enabled network card, do not stop or turn off the machine ...
The laptop with Linux preinstalled at the factory will have a full Linux ACPI support should not overheating or drain the battery faster.
How to know the BIOS with ACPI support for Linux or solve problems or overheat, How is battery power?
Run the command:

This command will read the description DSDT tables are stored in memory and simultaneously foo.dsdt decompile the DSDT ACPI Source Language (ASL).
Open foo.asl out, search string "Windows", If you see the word "Windows" without the word "Linux" is your BIOS does not support ACPI for Linux.
Even if the word "Linux" in foo.asl but still hot when running Ubuntu machine, battery power, the more likely your laptop M $ was forced to exclude Linux. In that case, You can patch the DSDT for Linux ACPI full description. Caused a very long article here.

Those who "feel" of your computer hotter when running Ubuntu, should first check with the steps:
– Install Everest on Windows and sensors-applet on Ubuntu.
– If you are using Ubuntu 11.04, select GNOME Classic interface (No Effects) in the login screen, even before 11.04 off effects in the Desktop Effects away, then right click on the top bar and add GNOME 2 applet: an applet that has installed sensors to check CPU temperature, Hard Drive, CPU frequency scaling applet two is to regulate CPU.
– CPU frequency scaling applet Click and choose powersave mode. CPU frequency will fall to lowest (40%).
– Turn off the machine and let it cool (paddy fan to cool it faster)
– Turn on the machine and let idle for about 15 minute, CPU temperature record (2 core there 2 temperature, 4 core there 4) temperature and hard drive.
– Turn off the machine and let it cool
– On Windows and to spare in 15 minute, temperature recorded in Everest CPU and hard drive
If the temperature of Ubuntu > Windows from 5 degrees C or more, that is the problem. Otherwise, you do not need to do anything. You just off effects and powersave mode is OK.

The bad news is Ubuntu since 9.10 will not support the use of the patch DSDT more.
BIOS _OSI(Linux) Ignored is the normal query. BIOS simply want to know the operating system running Linux Is not, and kernel answer is no. According to the dev, if the answer is going to cause some problems (I do not really know what this). You may read more here.

You can try 1 in the following way, if they overheat after checking with the steps above:
– Press e to edit the GRUB boot time options. Add acpi_osi = Linux at the end. This option will answer queries of the BIOS to the operating system is running Linux.
– Press e to edit the GRUB boot time options. Add acpi_osi = "Windows 2006" at the end. Equivalent to the use of ACPI for Windows Vista. [Can cause a kernel panic]
– Press e to edit the GRUB boot time options. Thêm acpi_osi=”Windows 2001 SP2 "at the end. Equivalent to the use of ACPI for Windows XP SP2. [Can cause a kernel panic]
Each test, you should boot from cold mode and compare the temperature. If still no improvement, the only workaround is to invest heat sinks.

Original article