Slow updates with sACN (E1.31) / DMX Out for WS28xx LEDs

I’ve been confused by this issue for the past couple weeks so I figured I’d look for help here…

I’m using Brian Amos’ DTG_E131 Teensy-based pixel controller with TouchDesigner. GitHub - brianamos1/DTG_E.131 Everything works great, except it appears pixel updates are only around 2 FPS. The workaround has been turning off v-sync and cranking up the framerate in Touch to ~300 FPS. At 300 FPS in TD the pixels seem to update around 30-40 FPS (just judging visually).

Any ideas what might be going on here? I have tested with older files that have worked fine with Advatek and other pixel controllers, so I’m guessing the issue has something to do with the DTG_E131.