Game FPS is lower than benchmark

[SkyKirbine]

I got my fancy new XPS 15 with an i5 6300HQ and a 960M. But my CSGO framerates were lower than what the benchmark said. The benchmarks for the same game and same hardware is 120 fps high, 1080p. But I was getting around 50 fps at that setting. Why is this happening

 

[Gagan sarpanch]

full specification of your pc ?

 

[SkyKirbine]

full specification of your pc ?

i5 6300HQ, 960M, 8gb ram, 4K screen, 256 GB M2 SSD