Google just pushed a much-needed update to its latest Pixel 4 and 4 XL smartphones regarding the 90Hz refresh rate issue. However, there are some things you have to know about the new firmware. Firstly, the high-refresh-rate mode is enabled throughout all brightness levels only on the big Pixel 4 XL. The Pixel 4's 90Hz range, on the other hand, is extended to 42%, meaning you will get the smooth display feature as long as you keep above that brightness level. We assume this is because the smaller pixel has a tiny battery, so Google is still looking for a way to preserve battery...
Source: https://www.gsmarena.com/an_update_enables_90hz_on_the_pixel_4_at_lower_brightness_levels_but_theres_a_catch-news-39956.php
