Lagging in league of legends but have optimal specs

binhp

Honorable
May 25, 2013
2
0
10,510
These are my specs
http://gyazo.com/385ab80ad3a2068374be8bd3f94b9f7a
http://gyazo.com/e0ea9eddeb44950f090be87953648a5f
When the game starts I get around 60-80 fps. But in teamfights I drop down to about 30-40. And after awhile of playing my fps stays around 35fps and doesnt go back up to 60. I see my friends with fps capped at 60 and it always stays at 60 and never goes up or down in teamfights. I tried changing my graphics lower but my fps pretty much stays the same as when my graphics were higher. I have update my graphic drivers and pretty much everything on this guide https://support.leagueoflegends.com/entries/20183433-Improving-FPS. Can I get some help?
 

binhp

Honorable
May 25, 2013
2
0
10,510


My Cpu is Athlong II 640 Quad Core, HD radeon 7850, 4 gig ram. my reccomended resolution for monitor is 1280 x 1024 and i play on 1280x780. and i have tried turning shadows off doesnt help.