We don’t even have to assume a new Pixel flagship phone is coming this year — for the first time, Google has announced features of its new phone before the big reveal. Google already showed off the back of the phone and talked about the Soli radar sensor, but we haven’t heard any official details on the screen. The next best thing after an announcement is code features from Google engineers, and XDA found some lines in Android 10 that support the report of a 90Hz screen.
The standard for mobile device screens has long been 60Hz. It took a long time for Android to even hit 60 frames per second in the UI consistently, but Google has prioritized smoothness in the last few versions of Android, and it optimizes Pixel phones aggressively. Laptops and desktop monitors have long advanced beyond 60Hz with 100, 144, and higher refresh rates readily available for a small premium. However, computers have a lot more power at their disposal, and phones need to remain efficient and pocket-sized.
It has only been in the last 12-18 months that high refresh mobile displays have become viable. Razer launched the original Razer Phone with a 120Hz display, but that was an LCD with serious efficiency problems. It ran at 90Hz out of the box, and even that drained the battery quickly. Asus improved matters with the ROG Phone, which had a 90Hz OLED panel. OnePlus launched the OnePLus 7 and 7 Pro earlier this year with a high-refresh OLED as well.
Several weeks back, the first reports of the Pixel 4’s 90Hz “Smooth Display” appeared. Now, XDA has spent some time digging through the just-released Android 10 open source code and found supporting evidence. Android contains a service called SurfaceFlinger, which links apps and system UI with the display controller. Naturally, the SurfaceFlinger service needs to be aware of the display refresh rate. SurfaceFlinger in Android 10 includes a manual 90Hz toggle that wasn’t present in previous versions of the OS.
In the current build of Android 10, the 90Hz mode exists as a temporary solution for testing purposes — a permanent version is already in AOSP, too. The code notes that the switch should only be used on “P19 devices.” Presumably, that means the 2019 Pixels, and not the Pixel 3a. Those budget phones launched last Spring, and they’re 60Hz. So, it’s a foregone conclusion that the Pixel 4 and 4 XL will indeed have 90Hz displays.