First of all, the current search function is definitely outdated. Not only that, it is not designed to search a database bigger than 200MB. As ours is 7.7GB, you can see the problem with the current engine.
We recently paid to have a much stronger search API installed at the root in the server itself. As this is something which required shell access, it's not something I was able to do. Instead, the hosting company did.
While Sphinx search is enabled for the forum, currently, it's not yet set up in the archive. The reason for that is that the search script itself has to be rewritten to allow for it to be used, and to make it so we don't go into query overload when it does. As the Sphinx engine allows for 2000 returns on a search, I do have to be careful in just HOW this is done, or the search function won't work AT ALL.
I'm also redoing the search FORM, so that we can have more search options than what is currently there, such as the ratings field.