CPU not even breaking a sweat. All 17 IMUs are returning good data (with quaternions) in synchronized frames. Render was only running at 5Hz or so in this video, but real frame rate of the data stream was 20fps.
Sensor rates were ~100fps, but we have since run at 400fps with full AHRS quaternion on each IMU. That comes out to ~6800 AHRS calculations/sec, and it appears we still have headroom.
With the debug console disconnected...