Just for testing, could you try switching to Plain text and see if tab-switching is faster for that (that'd be when switching to a plain text file)?
Yes, much faster.
Another suggestion, maybe you could withhold rendering of the document for a short while, so if a press Cmd+Opt+arrow repeated times to jump to a distant tab, it doesn't waste time rendering every tab inbetween. (I'm aware of the cmd+number shortcuts, can't get used to it though)