Hello Jorge
I will reply in english for the rest of the list as well 😊
The two intel based machines are used as web servers only, and the Sun server only for Oracle. Oracle might use the two processors, I don't really know the inner details on how multithreaded Oracle is and how it works on Solaris but I presume that it will make use of the second processor when needed.
We have a site, called the cybercentre, built in Zope and it's not static at all, it has some discussion forums, a la slashdot. The main site (www.greenpeace.org) is built using OpenACS.
And yes, the two web servers are behind a load balancer. I don't have the details of it since that is provided and maintained by the hosting company. I never had to deal with that, fortunately 😊