This is just an impression at this moment, but I haven never encountered SFDC Developer Console becoming unresponsive this often before. I noticed it on two sandbox orgs that are currently on Winter '14. When it happens CPU usage just goes to 100%, or 100% for one core, so in my case it's 25%, and I could hear the fans start to go crazy. This seems to happen the most when retrieving test results, and the crash affects the tab that launched the Developer Console as well. Both would have to be killed (for Chrome), or worse, the whole browser is dead (for Firefox).