Dell Precision M6800 is not compatible with Windows 8.1 Pro x64(adaptive backlight, adaptive brightness)


Jun 10, 2014
I have a problem with my laptop, below are all details. Please who has M 6800 with Windows 8.1 Pro
could you disable (Nvidia Optimus technology) in BIOS and then check if this problem exists or not on your laptop. Please write me about your results!

1) Dell Precision M6800 laptop (Intel HD 4600 graphics, Nvidia Quadro K3100M),
switchable graphics (Nvidia Optimus technology) is disabled in BIOS;
2) Windows 8.1 Pro x64, all firmwares, BIOS and drivers are the latest versions, all latest windows updates
are installed (I performed a clean OS installation, then installed all necessary drivers, then installed
all Windows updates, no additional software were installed);
3) I always use "Maximum Performance" power plan with the following settings in its section "screen":
-- turn off display (on battery: 10 min, plugged in: 15 min),
-- display brightness (on battery: 85%, plugged in: 85%),
-- dimmed display brightness (on battery: 85%, plugged in: 85%),
-- enable adaptive brightness (on battery: switched off, plugged in: switched off);
4) There is uniform dark grey background on the Windows desktop (this background might be any other
dark color, uniform or not, without any bright areas).

Display brightness changes in spite of the adjusted settings in active power plan. The problem exists
in two cases only: (i) I work on battery; (ii) transition from battery to mains or vice versa. In case "i"
display brightness increases when a bright object appears on the uniform dark grey background of my Windows
desktop (for instance if you run notepad.exe and its mainly white window appears over the desktop) and
display brightness decreases when the above bright object disappears from the uniform dark grey background
of my Windows desktop (for instance if you close or reduce to the taskbar the notepad.exe window). In case
"ii" display brightness decreases when you pull a power connector/plug off the laptop and increases when
the connector/plug is plugged into the laptop again.

This issue does not have a place if switchable graphics (Nvidia Optimus technology) is enabled in BIOS,
and the laptop screen is driven by, I assume, Intel HD 4600 graphics. As I utilize on my laptop
10-bit color depth workflow and correct color reproduction, it's much comfortable to work without
switchable graphics. I tried all latest video drivers, from both the laptop manufacturer web-site and
Nvidia web-site drivers including their latest beta-drivers, but the problem exists regardless of
the driver version installed. There isn't the problem under Windows 7 Pro x64.



Sep 17, 2012
Well Problem 1 seem's interesting and I don't have a M6800 (I have a studio XPS 1600) but I work with a lot of dell's since my company is a dell reseller but haven't dealt with a nice laptop like that yet.

But problem 2 seems normal actually. In the BIOS (Not sure if this is true for yours but it is for mine) there is a section for Display Brightness for AC and Battery. This will override your brightness settings. usually on battery its set lower (Like 4 or 5 out of 10) and AC is on max. Again if you are AC and have it manually set to max or even all the way down it will set the brightness to what ever its set for battery power. So do what i did. Find the Battery section in the BIOS and for the Display just change it to max on battery and AC then it won't change anymore when you remove and connect the AC adapter.

Now just understand problem 1 a bit more and i may have a similar issue with my laptop when connected to my TV though HDMI. When i watch a video and its a bright screen its nice and bright, but when i get a darker screen the brightness of the whole TV's dims down and honestly sometime's its hard to see. This sounds like what you are having on your screen. I don't have this issue on my laptop or my graphics card (I have a single graphics card. ATI Radeon Mobility 4670 1GB) but have this issue on the HDMI on my TV. I should try this on my Dell monitor just to see if it has the same issue as well. might be the TV. But i hope i have at least helped you out with Problem 2
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