Screen flickers

[Ural Kavraal]

My 640 xl's screen flickers when I set display low light. Is it normal

 

[Derausgewanderte]

no, that is not normal. On mine any setting other than automatic is rock solid no matter what lighting conditions.
First thing to try is a soft reset to see if it's OS or software hiccup.
good luck

edit: well, it maybe normal. see Daniel's post below.

 

[Daniel Gilbert M]

Derausgewanderte, It is normal.
I had the same issue on the 630 DS as well.
It seems like the SD400 cannot handle ultra low brightness (power management combined with the cheap LCD). It's a hardware issue.
On the 630 DS, the effect is noticeable while on the 640XL, not that much (only if you look closely).

To reproduce what the OP said,
Go to display settings - brightness profile - and set the "low level" slider to the extreme left.
Then put the phone brightness in low and look closely.

This is noticeable in 8.1 U2. Don't know what happens on W10TP.

 

[Derausgewanderte]

I'm on W10M latest build. Maybe they addressed this. I don't see flicker.