Identifying the existence of hwcomposer of Project Butter in Jelly Bean I've heard that some 3rd party ROMs for some devices, such as the Galaxy S3, are based on Jelly Beans. But when asked why it's not as smooth as what the makers of Jelly Bean claim they would say it's because hwcomposer, the primary component of Project Butter that makes everything smooth, is not yet there.

How do I tell if my currently installed Jelly Bean ROM has the hwcomposer? I just couldn't tell the difference in smoothness coming from ICS. I'm not saying it's laggy but I was expecting an improvement and no more occasional lags.
On startup, check adb logcat for an init message that mentions the hwcomposer.

If you have a logcat viewer on your device (such as CatLog), you can use that, too.