Black spots while doing speed ramp

Can i get an answer how i can with black spots during speedramp

I was trying to make speed ramp with a motion blur for a montage clip

When i render the part that had the most speed ramp edit

it has some sort of black spots, i tried to not render it with the motion blur and its still here, so it thought it supposed to be on the slow motion during the speedramp

Or there could be another issue such as not compatible graphics driver? Because i had that warning before running premiere 

Thanks