Is WordPress fast enough for a heavy traffic project?

I was always a WP guy, built many small sites with it. I will create a new community with a big fanbase and I was wondering if 3.1.3 is fast enough? I didnt have the opportunity to work with it since 3.0.

How does it react with heavy traffic web sites? Is it something that will make me worry enough to search for a lighter CMS or should I rely on it even with hundreds of visitors per day? I know about the tricks/tips to make it feels faster but is it by default ?

I don’t think there is any considerably advanced CMS that you can throw high traffic at and expect it to handle it without any configuration effort.

Can WP be used for high-traffic site? Of course and it is being used as such by many sites.

But it should be WP on decent hosting and well-configured software stack, rather than WP on cheap shared hosting with Apache defaults and no caching whatsoever.