Hi,
In addition to the above, I have a model of Viao that uses Intel graphics card HD3000, Intel does not have an updated driver for this graphics card for Windows 10. I've been fighting this since I upgraded to windows 10 - All the below was addressed and with the Sony Vio auto brightness turned off finally no more problems after switching off auto brightness in Viao menu.
1.Power- Go to " Control Panel> All Control Panel Items" Use small icons to see item 2
2.Open Intel Graphics and Media Control panel - Power - Set Maximum performance ( Disables power saving feature)
3.Update all your drivers using windows driver update, or individually, or go to Itel website, they have a driver update program you can install
4. Settings in windows menu, Display, Advance power settings, Set to High performance to match Intel setting, default is balanced. You can also choose what to do when lid is closed or power button ( brightness)
See links for additional information:
http://www.intowindows.com/how-to-disable-auto-or-adaptive-screen-brightness-in-windows-10/
http://www.intel.com/content/www/us/en/support/graphics-drivers/000020962.html
The above will maximise performance, but will reduce your battery life.