A friend of mine was curious on the graphics performance of my rMBP. I let him install Starcraft 2 on it and it looked like there were 59 fps at High settings at a 1680 resolution. However, when he tried moving the cursor to the edge of the screen to look at and pan to one side of the map to the other, there were periods of "brief pauses" along the way. The fps looks very high and is very speedy except for the slight pause/stuttering. Is this a problem with my graphics card? Do others encounter this glitch?