Your system has dual graphics card and optimus enabled. you need to turn off the discrete graphics card. Otherwise both are enabled and lead to high temperature.
First look for a BIOS configuration to turn off the discrete one. (As a dell user, I am sure the option isn't there, though check once)
Instruction for installing Bumblebee to turn off discrete GPU and enable only when required
Please read - Ubuntu docs link for updated info. The following part is taken from this link.
Type the following in terminal,
sudo add-apt-repository ppa:bumblebee/stable
sudo apt-get update
For more up-to-date nvidia drivers, you need to add another PPA. As of 12.04, this is still necessary for Nvidia GT 6xxM cards. It may be optional for the GT 4xxM and GT 5xxM series on 12.04. When in doubt, just install it. The command is:
sudo add-apt-repository ppa:ubuntu-x-swat/x-updates
sudo apt-get update
To install Bumblebee using the proprietary nvidia driver:
sudo apt-get install bumblebee bumblebee-nvidia linux-headers-generic
if you are only interested in power savings, don't do above step. Instead execute
sudo apt-get install --no-install-recommends bumblebee linux-headers-generic
To know, whether discrete GPU is off after reboot ,
execute after reboot
dmesg | grep bbswitch
you will see something like below
[ 25.305974] bbswitch: version 0.4.2
[ 25.305983] bbswitch: Found integrated VGA device 0000:00:02.0: \_SB_.PCI0.GFX0
[ 25.305991] bbswitch: Found discrete VGA device 0000:01:00.0: \_SB_.PCI0.PEG0.PEGP
[ 25.306182] bbswitch: detected an Optimus _DSM function
[ 25.306192] bbswitch: Succesfully loaded. Discrete card 0000:01:00.0 is on
[ 25.325482] bbswitch: disabling discrete graphics
[ 25.325620] bbswitch: Result of Optimus _DSM call: 11000059
If you just want to disable nvidia card, no need to learn followings
Usage Instruction :
To run a program with nvidia card, use
optirun command prefixed in terminal.
Like to run
glxspheres with nvidia card type
To run firefox type :
optirun firefox &
Note: If you intend to run 32-bit programs like Wine and using Ubuntu 11.10 Oneiric or later, install 32-bit libraries with:
sudo apt-get install virtualgl-libs:i386 libgl1-mesa-glx:i386 libc6:i386
How well will Nvidia Optimus cards be supported in 12.04?
How well do laptops with Nvidia Optimus work?
Can't use nvidia card/driver on optimus notebook