Mike Richards here from R*. Be alert around 12:00 GMT tomorrow for a patch for both the 360 and ps3 versions of GTA IV - we've been working 'round the clock to fix this issue, and seem to have found the problem. For those of you who care, we render the screen in the backbuffer and then flip it onto the front buffer. During those freezes, the code hits a glitch and stops flipping - the reason some of you manage to only have freezes for a few seconds while the sound still runs.