Massive FPS drops when mouse over objectives | Keyboard delay

So basically as the title says I get massive FPS drops whenever I move my mouse over any objective-ish entity, meaning : turrets,inhibitors,nexus,jungle buffs (sometimes), dragons, herald and baron. Since I am a main jungle this completely cripples me and my chance at "perfectly" smiting.I usually don't smite at all unless completely sure and the only way I clear those objectives is to right click and then move my mouse away in order to get SOME FPS back... This has been happening to me all the time and I can't really tell why. It happens only on the objectives.

There's also a problem with my game having moments when it's getting commands from my keyboard delayed by 1-2 seconds. It makes me look like a monkey for flashing backwards, warding middle of the lane but also killing me when it happens in a fight. But as I said, it's only a keyboard thing. My mouse responds perfectly and if I had the reflexes and speed of Neo I could play normally if I used my spells by clicking them.

These things made me pretty much uninstall league since I don't want people to lose games because of one feeding monkey that is as usefull as Teemo in baron pit.

Don't know if this is a bug or a gameplay thread so I am putting it into the gameplay since it's only a personal problem. Thanks in advance.