I installed 5.2 on my amd64 laptop. I'm using the altroot softraid method
of encrypting /, posted by Nick on geekyschmidt.com. Anyway, the first boot
hung on "cpu3: AMD erratum 721 detected and fixed". I powered off and
rebooted, and haven't had a problem since. I'm not able to reproduce it, so
I don't think further details are warranted.
I'm reporting this just in case others encounter this issue.
Thanks very much for the new pthreads. It's working great.