Hi @wklie,
Thanks Peter.
I have/had the same behavior (tracks/titles skipping) with a Fritzbox 6490 and now 6591 - of course both Fritzboxes. If I disable the Packet Acceleration the speed drops from 500-900Mbit/s to 10-30Mbit/s and if I reboot the router everthing is back to standard (with Paket Acceleration). I opend a support request at AVM (Fritzbox).
Thanks for trying to help. 