RE: Precision M4800 : Input lag at log in, Switchable graphics not functioning, GPU fan "chirping" when it starts up.
I too recently purchased M4800 with win 7 pro. I upgrade to win 10 but what a mistake. I got the dreaded cursor lag and occasional crashes. Clean installed windows 7 again and went to download the video driver but I am now only seeing one from back in March. This now cause lag in windows 7 as well. I am currently forced to run off default vga driver as Intel HD graphics are disabled (I have the 4K screen version). I hope this gets sorted out soon!!