Dedicated Graphics Card

[Rishatale]

I have a Toshiba, running intel core i7-4700MQ, 16 GB ram CPU @2.4GHz
However, i also have a Nvidia GeForece GT 740M 2GB dedicated graphics card. I have tried updating the graphics card, and changing the settings however when i try to play games (League of Legends, for example) my FPS isn't stable.
This is a new issue for me, as i usually play between 50-60fps and now it jumps between 8-50 never staying stable. However, when I change to my integrated graphics i haven't the same issue (though it's not as high a frame rate, if i lower the graphics setting the fps becomes stable between 55-60.)

I'm not a tech person, I've pretty much learn everything i know through google. However I can't seem to figure this one out and would like some help please!

Edit: I have uninstalled and done a clean install of my graphics driver, and still have no change.

 

[DeathRabit]

If driver issue.

Use this http/www.guru3d.com/content-page/guru3d-driver-sweeper.html
And follow instruction :
Use the official uninstaller(s) of the driver(s) you want to uninstall.
Reboot your PC in Safe Mode.
Run Driver Sweeper and select what to clean.
Analyse lists all the entries possible to remove, cleaning removes the entries selected.
Reboot to normal mode.
Install fresh drivers.