I recently installed elementary os freya 0.3.1 . At first , when I tried it from usb , the os ran smoothly considering it wasnt a native install. However, after I installed it ,it lagged pretty bad! Files took forever to load and close and graphics were really choppy. Plus, the fan wouldnt slow down and made noise the whole time. I tried installing the nvidia drivers from the Additional drivers tab but nothing changed . I have a compaq presario cq61 which seems totally compatible ,and every other distro I have tried runs pretty smoothly.Any suggestions?