see https://askubuntu.com/questions/697623/ubuntu-15-10-display-blur-lines-and-hang-issue-with-intel-core-2-cpu/701216#701216
see https:/ /askubuntu. com/questions/ 697623/ ubuntu- 15-10-display- blur-lines- and-hang- issue-with- intel-core- 2-cpu/701216# 701216