Need help fps problem

this is my graphic card :NVIDIA GeForce GT 525M and 8 gb ram. i used to have 150-200 fps when i was playing lol in 2012 in season 3-4 but now in season 8 my fps is 20-40 with no fps drops thankfully, but i see my friend have intel processor core 2 duo with same 40 fps. why? any solution?

is it because my Nvidia is really old and no longer powerful to play latest game? or maybe because i have viruses or something that can make my pc lagging?

sorry for bad english and pls comment i would really appreciate that thanks