@akcent SLIC Toolkit doesn't work reliably under UEFI systems; it can't find the RSDT pointer. Use RW-Everything.
rw files also pose a problem. I do not open. So I suggested WINPE. WINPE contains all the necessary tools.
That's not something you can achieve simply by using a modified BIOS, it depends on how the mobo is designed. With the V3 771 the dGPU was not connected to the display, making it impossible to not using the Intel HD, most likely it's exactly the same case with the 772, meaning if you change the display settings then you will end up with a black screen.
Thanks for your remark. When I play HD video at 60 fps, I have frames that are dropped from time to time. It doesn't come from the player, it is really after that (so on graphic card side I guess). It is really annoying. I see that when I play video the Nvidia card is not used at all (thanks to Optimus). I therefore wanted to try to "force" the use of Nvidia card all the time to see if it removes those "frame drop" issues. I know that at some point both Intel and Nvidia merge their pipe in order to display the frames, but I don't know if the problem is happening after or before this pipe merge. To summarize, that's true that maybe bios mod will not solve anything. But I wanted to have a try since I don't have any other idea (beside putting this expensive laptop on ebay and re-buying a "working" one )