How about posting INFORMATION REQUIRED WHEN POSTING A QUESTION, like:
APPLICATIONS AND GAMES you have tested
r9 m375 isn't that strong, perhaps r7 260 desktop card level at best.
Processor: Intel(R) Core(TM) i7-5500U CPU @ 2.40GHz (4 CPUs), ~2.4GHz
Laptop Model- lenovo Z51-70
display res:- 1920 x 1080
RAM 8 gb
i have tried it on games - Rainbow six siege, Lara croft 2, Rocket league
Your laptop has 2 graphics cards and uses switchable graphics tech like arcticwind above suggested. Have you tried checking if your dedicated GPU is being utilized instead of the intel one?
Also, this is your laptop review: Lenovo Z51-70 (Radeon R9 M375) Notebook Review - NotebookCheck.net Reviews
At the bottom of that page, there are benchmark and games tests, _with settings used_. Do your results match the ones there? If you are playing at native resolution of 1920x1080, I would expect your frames to be around 30 fps with that GPU, tough you could get more if you lowered ingame settings. Don't forget to disable VSYNC or radeon chill.