I have a Clevo P650SE-A(Sager NP8651) with NVidia GeForce GTX970m and Intel HD5600, the laptop does have a LED that shows if the discrete GPU is being used or not.
I got nvidia drivers and prime successfully working on both Ubuntu 14 and 15, I have noticed that while turning on, off or going to sleep the laptop turns on the dGPU LED.
The problem is that it leaves the GeForce on while sleeping. Which leads to overheat with the fans off and a waste of 15-20% per hour while sleeping. It is actually heating and using more battery while off than it does on.
Hibernating is not an option because it cannot resume after hibernation(black screen with cursor) and I don’t really want it to hibernate since I’m used to suspend it many times per day.
This happens with Ubuntu 14 and 15. I’m using the 3.19 kernel because the 4.2 does not seems to support my video card.
The sleep problem does not happens on Windows using optimus.
I’m not using UEFI, but it happens with it too.