Laptop slow and unresponsive when running on battery

My laptop is slow and unresponsive when running in battery; it works fawless when connected to ac power. In the past I used to have tlp/laptopmode-tools but since Linux 3.x I have uninstalled both. Battery last long but usability is poor. This is happening on a dell xps 13 with ivybridge CPU and Archlinux x64 with either stock kernel or ck kernel, gnome shell. Is there anything I can tweak in order to get better performance/responsiveness on battery (I'm willing to loose some battery life).