A reboot doesn't fix anything, it can go straight back to running slow, in fact most of the time that's exactly how it is after a reboot. Sometimes it will work fine for a few hours but those cases are probably only 1 in 10 runs, perhaps even rarer. I've tried running with the single TTS option selected too and that makes zero difference unfortunately. I'm using Ivona Amy TTS, the one HCS used themselves to make ASTRA.
IF it's a system fault then 100% of the current beta team for this particular pack have the fault at some point.