We updated the dedicated server only build (appid 294420). It uses the same version number (A9.2 b14) to be compatible with the existing clients. The update was due to a change in Unity 4.5.3 that obviously handles the VBlank different then in previous version. This caused a dedi server to take full CPU time of a single core even if no user was connected. This problem should be fixed with the latest update (steam buildid 373581)