I think most server machines are probably pretty loud. They're designed to go in data centers where noise is not a factor. They put a lot of components in a somewhat small space, then they put passive heatsinks on the CPUs and blow air through the whole case, including the passive heatsinks. The fans are really loud because they are both small and powerful.

If you wanted, you could take the top off the case and then put bigger, quieter fans in, or perhaps put larger, quieter active desktop heatsinks on just the CPUs. I think this would be okay, I don't think the rest of the motherboards usually require the fans, but I could be wrong.