Chromecast has taken the community by storm, and Google is already sending out a performance enhancement update. Have you received it yet? Of course, there is know way of knowing that. It is not like a device where you constantly check the System Updates hoping the update is in there. No, this update will happen automatically, and it has said that this update will provide improved reliability, as well as improved security, and like I said at the beginning, performance enhancements. Let us know know if you feel your Chromecast service has been running much better.
Source: Talk Android