Pbr shaders using render dragon doesn't work properly

using a pbr shader through render dragon works but the game gets low frames and choppy shadows. Tried other shaders too and the problem persisted through all of them getting low frames and choppy shadows. I have a 8gb ram device with mali gpu. 

Link-https://1drv.ms/v/s!AplSxqmNbS0FaisLVBM0CzTFBS0