Interesting indeed. I talk very fast too, generally. In my presentations and talks(only few I had given), I used to talk fast and people will loose interest in the talk. I got many good feedback to slow down a bit, I did it by adding pauses at relevant points (still in practice).

I have kind of two hypothesis especially for me. Why I talk fast?

a) My local/native language is fast paced. May be due that in English too I am talking fast.

b) My mother also talks very fast. May be I got certain traits from her.