I've noticed since the last graphic driver update from Intel (now it's version 188.8.131.526) some troubles with the video.
- Working in battery mode
before next start, I connect the power supply
=> then I start up the laptop, and voila, There are a lot of strange 2-3cm stripes vertically through my screen. After a reboot everything is fine again.
If I connect the power supply after already running windows, there are no problems
Please read this thread. Bottom line: downgrade to the previous 184.108.40.2065 driver. Can be downloaded from Lenovo now.