Currently running Elementary Luna on my laptop with switchable graphic cards. Laptop some time goes hot near the touch pad area with fan noise and hotness.

Did a bit of research and find out that it was ATI card ON by default. Battery usage was 1 to 1.30 hours on ATI by default. I have ATI 6600M with Intel integrated graphic card. From my previous openSUSE experiments, tried some solutions and can say things are much better now with Intel card[switched]. Battery life goes from 1 / 1.30 to 4 / 5 hours dramatically, no more heat issue and noise. Temperature dropped to around 50C for CPU and around 47C for HDD, which i still think is a bit high(working on it). So here is what i did.

Just for monitoring purpose, install lm-sensors and hddtemp.

sudo apt-get install lm-sensors hddtemp

sensors-hddtemp <>

Now edit the following file with sudo(assumed terminal is open):

sudo vim /etc/rc.local

Add the following lines before exit 0.

chown -R $USER:$USER /sys/kernel/debug
echo OFF > /sys/kernel/debug/vgaswitcheroo/switch

Reboot, and see if that helps. You can view in terminal which graphic card is active now:

sudo cat /sys/kernel/debug/vgaswitcheroo/switch

IGD = Intel

DIS = ATI [Discrete]

Sample result:

0:IGD:+:Pwr:0000:00:02.0
1:DIS: :Off:0000:01:00.0

Even can switch back to ATI [need to logout and login for this to take affect, discrete card will be active(ATI)](not tested):

echo DIS > /sys/kernel/debug/vgaswitcheroo/switch

To turn OFF the in-active card:

echo OFF > /sys/kernel/debug/vgaswitcheroo/switch