Originally Posted by
Weston@HPTuners
This looks like it could be a CPU resource issue when you are attempting to use iOS Screen Mirroring. The first lap where the track map is being drawn as you drive does take more CPU than subsequent laps, because it has to rescale and regenerate the whole thing upon each new GPS data sample. Your video showing the app's display lagging and updating less frequently certainly fits that theory as well. This CPU use would also be increased if you are using an external GPS with a higher sample rate than the phone's internal 1 Hz GPS, being that it's getting more samples per second.
You might try turning off TrackAddict's own video recording, if you have other cameras capturing the action. That could save some processing time.
The next app update (v4.0.5) will aim to reduce the CPU load during this first lap. The map's first lap refresh rate was cranked up for many of the newer phones, so I'll back that down a bit.