I don't think I've ever gotten that far, what I do usually write is about 5 posts in that time, which is when I usually connect during the week, sometimes it's in 50 minutes or an hour and 20 minutes. Or it's 4 posts instead of 5 but writing about a post every 12 minutes on average in an hour I do.
If you're doing that and writing at the level that you are (which indeed is above average for bitcointalk IMO) you're definitely not burst posting. The way I see it, burst posting is like hardcore pornography. It's hard to define it precisely, but you know it when you see it (that's paraphrasing SCOTUS Justice Potter Stewart, FYI). When I look at my feed of unread threads and I look down the list at the most recent poster and see that the same member's name appears in most of the first ten threads and maybe even more, when I look to see what that member wrote it's a few lines of nonconstructive, generic nonsense. Every single time--and I've seen that happen more times than I'd care to.
You got accused of burst posting? That's just plain stupid, and your accusers ought to flog themselves in shame.