9/21に8.0-RC1が出たそうなのでtag=RELENG_8でcvsup.freebsd.orgからcvsupしてみましたが、
UPDATINGがこんな感じで更新されているように見えません。これで良いのでしょうか？

NOTE TO PEOPLE WHO THINK THAT FreeBSD 8.x IS SLOW:
FreeBSD 8.x has many debugging features turned on, in
both the kernel and userland. These features attempt to detect
incorrect use of system primitives, and encourage loud failure
through extra sanity checking and fail stop semantics. They
also substantially impact system performance. If you want to
do performance measurement, benchmarking, and optimization,
you'll want to turn them off. This includes various WITNESS-
related kernel options, INVARIANTS, malloc debugging flags
in userland, and various verbose features in the kernel. Many
developers choose to disable these features on build machines
to maximize performance. (To disable malloc debugging, run
ln -s aj /etc/malloc.conf.)

20090915:
ZFS snapshots are now mounted with MNT_IGNORE flag. Use -v option for
mount(8) and -a option for df(1) to see them.

20090813:
Remove the option STOP_NMI. The default action is now to use NMI
only for KDB via the newly introduced function stop_cpus_hard()
and maintain stop_cpus() to just use a normal IPI_STOP on ia32
and amd64.