1566 and 1512. I had boot issues over 1620 as well, so I went with 1512 next go around...then tried 1566 as well.
When my clock is too high, it won't even boot properly. Choosing 1566 or 1512, and it reboots at some point between 1 minute and 20 minutes.
In another thread, I was told to change some init.d and post_boot things around, and it didn't help. Until I get more feedback on what to try next, I'll just keep running Buttered Toast.
I'll try to look that thread up when I get home. I have yet to try Anthrax with another ROM. That could be my next step, but I don't really want another ROM. Mobster HD is just what I like. Testing with another ROM would just tell me if Mobster and Anthrax play well together on my phone, or if it's just my phone and Anthrax that don't play well together.
Either way, it's my phone that is likely special, as many people here run Mobster HD with Anthrax without any issues.