As someone who tends to set their brightness on around 60% and leaves it at that all the time I never thought I’d run into issues caused by this with the operation of the Pixel 4. It seems I was wrong.
Mishaal Rahman, Editor in Chief at XDA, performed some experiments on his Pixel 4 after seeing comments on Reddit about a user who found issues with smooth display (90Hz) turning off at certain brightnesses and received some troubling results.
Holy crap. Google Pixel 4 changes between 60Hz and 90Hz based on screen brightness.https://t.co/J6J2SjNBEw
I tested using ADB and logcat.
If brightness < 75%, display id = 2.
If brightness >= 75%, display id = 1.
— Mishaal Rahman (@MishaalRahman) October 23, 2019
It seems that the Smooth Display will turn on and off at certain brightnesses. Above 75% brightness the display will operate at 90Hz and below that will be switched off and operate at the paupers 60Hz refresh rate. It is worth noting that this does not occur when there is bright ambient lighting so it seems that Google is turning down the refresh rate when the light levels are such that you are unlikely to notice.
It is unclear why Google have done this with the OnePlus 7 Pro and the Asus ROG Phone II not exhibiting this behaviour but it could be a battery saving technique — and given the already poor battery life of the Pixel 4 we are glad they did (or they could have put a bigger battery in…). To test out the refresh rate of your Pixel 4 head on over to testufo.com.
Google have commented on the findings to the Verge saying that the 90Hz is basically reserved for when consuming content or navigating the UI but preserve battery life it is lowered in certain scenarios:
In some conditions or situations, however, we set the refresh rate to 60Hz. Some of these situations include: when the user turns on battery saver, certain content such as video (as it’s largely shot at 24 or 30fps), and even various brightness or ambient conditions. We constantly assess whether these parameters lead to the best overall user experience. We have previously planned updates that we’ll roll out in the coming weeks that include enabling 90hz in more brightness conditions.
It is unclear what the new update will entail whether it will give the user more control over the refresh rate or if Google will just enable 90Hz by default in more situations.
There is of course a way force the 90Hz to be on all the time — Developer Settings –> Force 90 Hz refresh rate –> toggle on. We don’t recommend that though if you want or need your battery to last more than two thirds of the day having tested it the battery drained even faster and barely made it to lunch time.
It is good to see Google already working on updates to their already beleaguered Pixel 4 but the one thing they should be focusing on is extending the battery life — hopefully they can do that without having to dumb down the phone any more.