FPS low rate

i need help, i have a good computer but i still have really low fps rate sometime it drops as low as 1 fps and i dont know why tho here are my computer specs

Operating System: Windows 10 Processor: Intel(R) Core(TM) i7-4510U CPU @ 2.00GHz 2.60GHz Installed Memory RAM: 12.0 GB Display Adapters: Intel(R) HD Graphics Family & NVIDIA GeForce 840M and 2.0GB video memory (2176Mb)