Oppo F9 has ARM-Mali G72 MP3 GPU. The peak frequency of the GPU is 800 MHz.
Oppo F9 has a dual rear camera set up, 16MP and 2MP. The main 16MP rear camera has an aperture of f/1.8 while the second 2MP camera has an aperture of f/2.4.
Yes, Oppo F9 is a dual VoLTE mobile phone. You can use 2 4G network sim cards at the same time.
The most striking feature of the Oppo F9 is the big display with the waterdrop notch. It is well designed, delivers good battery life, and offers decent performance for the price.