zackon1 - as jrs stated you can use use Quartz Crystal - why you might wonder - answer is - because it is an offline renderer and that means far less lag than could result from running a live screen capture.
Quartz Crystal also supports all those 3rd party plugins and patches [Standard and non Standard API] that going down the "Export as Quick Time Movie" won't fully support [Unsafe patches and Plugins].
If you are only using stock patches then you could try going down the Export as Quick Time Movie option, though this only works for the best when you have QTPro installed.
See [http://www.udart.dk/2009/02/25/rendering-quartz-composer-compositions/]
You could also have a good look at Syphon - low levels of lag reported from many users.
Use Quartz crystal or there are heaps of different ways which you can find through searching these forums
zackon1 - as jrs stated you can use use Quartz Crystal - why you might wonder - answer is - because it is an offline renderer and that means far less lag than could result from running a live screen capture.
Quartz Crystal also supports all those 3rd party plugins and patches [Standard and non Standard API] that going down the "Export as Quick Time Movie" won't fully support [Unsafe patches and Plugins].
If you are only using stock patches then you could try going down the Export as Quick Time Movie option, though this only works for the best when you have QTPro installed.
See [http://www.udart.dk/2009/02/25/rendering-quartz-composer-compositions/]
You could also have a good look at Syphon - low levels of lag reported from many users.