The spearhead server is indeed in beta. The guy who does it is aware of the high cpu usage and will be fixing it. As far as the MOHAA using high cpu, None of us that run/used to run a MOHAA server saw any unecessary CPU usage. You can check out the status of the project here:
http://www.icculus.org and also post a bug in the bugzilla and the guy will check it out.