We currently are using CCNet as our continous integration server. Most projects check for changes every 30 seconds (the default) and if needed perform a build (unit tests, stylecop, fxcop, etc).

We've gotten quite a few projects now, and the server spends most of its time near 100% cpu utilization. This has alarmed some of the development team, even though the server is responsive and builds are still about the same length of time they've always been.

Its been suggested that we lower the check interval to about five minutes. To me that seems too long, and we risk people committing code and then going home for the weekend and now there's a broken build possibly holding up others. In response, the suggestion is that if someone needs to know the results they can force the build. But that seems to defeat the purpose of CI, as I thought it was supposed to be automated.

My proposed solution is just to get another build server and split the builds amongst the servers.

Am I thinking about this the wrong way, or is there a point where if integration isn't often enough you're not really doing CI anymore?