I work in a computer repair shop and quite a lot of the time when we see lagging mice it's an indicator for failing HDDs.
Download UBCD (here:
https://mega.co.nz/#F!Mk0EgIAY!QCDxyHE1bzdRDxRCW1yb4w
) and burn it to a disc, then boot from it.
When you are in the utility, go to HDD\Diagnosis\ then select the program from your HDD manufacturer e.g: SeaGate Tools for SeaGate drives.
Let us know if you find anything.
If this isn't the issue, update your graphics card driver!