Dual Graphics cards to fast for LOL???

when I play LOL with dual graphics cards its ok for a little bit FPS is fine and Ping is Fine but when you start playing for awhile the picture starts to bug out the shading starts to go on the frits and coloring is all over the place like LOL cant keep up with how fast I am going on my comp any way to fix constant color disfiguration im thinking it might be your Adobe Air but not sure please any help would be appreciated :), oh and I've played on others games and runs fine so yea only LOL.