I got this laptop: Dell Inspiron N5010 with i5 2,40GHz processor, 8GB Memory and a Kingston SSD.
4 months ago my charger`s pin jack has broken, but it was still working. I noticed that the performance had decreased drastically when the charger was plugged in, so i bought a new charger, and all was working fine.
Last week my laptop was very laggy so i decided to reinstall Windows 8. After a clean installation, the same problems occurs with the charger.
When the charger is plugged in ( even if the battery is inside or outside ) the performance if very low. When i remove the charger and start the laptop with the battery the laptop works perfect.
The power options are set to High Performance in both cases.