My evo does the same thing. Even when I record in the next lower setting. I am not sure but it might have somthing to do with the SD card. I have the eight gig class two card that came with the phone installed. This card is nearly full, with just under 2 gigs available. Using this card the phone drops frames all the time. When I use my four gig class 4 that is empty I get better results. I am not sure, but I think the lower speed card cannot keep up with the data the evo is recording. If some people with different class cards would chime in we might be able to figure this out.