First of all, let me answer you that 120hz is not 90 frames.

120hz refers to the screen refresh rate, which means that 120 pictures can be refreshed per second, and 90 frames means that 90 pictures can be dynamically played per second. The two are related but not exactly the same. At present, mobile phones generally support independent selection of refresh rates, which have three levels: 60hz, 90hz, and 120hz. In daily use, such as using Taobao or browsing the web, a refresh rate of 60hz is sufficient. If you are playing games or watching videos, there will be a choice of 60 frames and 90 frames, so there will be corresponding requirements for the screen refresh rate, that is, 60hz and 90hz. High refresh rates can support corresponding and lower frame rates, but low refresh rates cannot support high frame rates.