[Diemenz]

Did you make sure you have the most up to date firmware?

I am using Intel drivers instead of the windows drivers on my surface 3 and although there is a bit more battery usage the performance difference on photoshop is considerably better.

I do not have a white screen flash when I start up, but that could be related to a program you have running on the desktop like facebook or similar.

For the youtube screen turning off issue are you using the metro app the metro browser or just the desktop browser?

I watch netflix on the metro browser (because the netflix app uses double the battery) and I never have the screen turn off during videos. Again this could be because i am using the Intel drivers.