Any special reasons why?

Are you talking about once you've installed phpBB-SEO? Are you noticing that your site loads faster with phpBB-SEO versus the unmodified phpBB 3.0.6?

Ah sorry for not making it clear, I though posting in this forum would be clear, but I meant the phpBB seo forum (this forum) itself.
Compared to other phpbb2 and phpbb3 forums, this one is a lot quicker which makes it a lot nicer to use.

I agree.

I'm sorry, I should have looked at what forum you were posting in before asking. I think phpBB-SEO.com is hosted on a pretty robust server platform and it is not as bloated and overcrowded as phpbb.com

phpBB SEO Server update
But the server is also installed on a very well rooted network (page generation time is usually connectible compared to the transmition time).

But it does not use APC so far, could be 6/7 time faster with it, especially since 3.0.6 introduced support for apc (among others, but since apc should be native in php6 ...).
Though, file cache is still a bit faster since 3.0.6 update with the new cache file format (flat reading were it was a php include), for the first time, cached queries are all faster than non cached ones