any updates on this?
I experience the same issue with a Toshiba laptop based on an E350. In details:
Flickering horizontal lines originating from the side of the monitor and reaching towards the center of the screen. Amount and position of the lines varies with each occurance, duration as well. These lines appear and go away after a certain amount of time.
Very similar behavior can be seen on these videos:
The motherboard has been changed already to no avail. Testing with a 2nd external monitor didn't help, and I can't reproduce the issue on the main display either.
Can't reproduce the issue (tried universal stress tests, cpu-memory-vga tests, etc.), going to idle for a long period of time, dimming the screen, doing sleep/wakeup cycles, etc. The issue is very random.
Toshiba C660D-16E, Windows 7 prof. 64bit, latest drivers from Toshiba website.
Based on sources around the internet the current best guess for a cause is the advanced power management, which dinamically changes the core speeds (in both CPU and GPU). Disabling these (turing off PowerPlay, setting Windows power management to maximum performance, etc.) didn't help though. Tried many different combinations of settings as well. Many other brands sharing the same hardware (E350 or E450) have the same issue, Lenovo, Asus, etc,