I was very confident with this built that it can atleast run league of legends cause it's the only game im planning to play on this build but while the graphics are nice even when its set to very high and has like 60-90fps on very high settings, the movements are very choppy and sometimes skipping even at 120+fps at medium - low settings.
I know nothing of LoL, but, per that speccy, that ram seems to be running a very low speed. Is that its rated speed? Athlon can go up to 2133 mhz, yours is at 798 mhz. Is an XMP in your bios for that Ram?
I would also check against a different game that is not online dependent, but for all I know part of LoL is not online. Best to remove as many possible factors as possible.
Your cpu should be good enough for a 2009 game. Per the LoL recommends, it looks like you should be ok.
Definitely close Chrome, it uses a decent amount of cpu and ram.
Also keep in mind if you are playing on a 60hz monitor and your frame rate is over 60, it can get choppy. Does LoL have vsync in its graphic options?
I would also make sure I was within the least acceptable resolution in Windows for that card and that game.