'm having the same problem, 98-100% CPU usage on one core, on a Mac, though. Been searching since I updated to see if anyone else has been experiencing the same problem.
The CPU usage is high when idling, and as far as I can tell it's not doing any work scanning or whatever, as I let it run for days and it never finished. I thought it had to do with the new music update, but it's been a few days now. When transcoding it goes from 100% to 104%, so there's no problem there.
I can post the log when I can reach the server later, but just wanted to chime in for now that I've been having the same problem ever since the update.