For all Thinkpad users, precisely L420 series, I had this problem for about half-year now, no suggestion works, neither the driver from realtek nor changing kernel versions.
The general problem appears to be if the signal is weak around 50% it starts to go nuts.
Best suggestion? If you can replace the laptop, if you don't have a warranty and maybe want a faster option just buy a Intel® Centrino® Advanced-N 6205 costs about 20$ works nicely with Lenovo laptops takes 5min to install.
For all Thinkpad users, precisely L420 series, I had this problem for about half-year now, no suggestion works, neither the driver from realtek nor changing kernel versions.
The general problem appears to be if the signal is weak around 50% it starts to go nuts.
Best suggestion? If you can replace the laptop, if you don't have a warranty and maybe want a faster option just buy a Intel® Centrino® Advanced-N 6205 costs about 20$ works nicely with Lenovo laptops takes 5min to install.
Good luck to everybody ;)