freebsd stable - Jul 2015 - Slow frame rate running stable running r285364M with Radeon 3850

Hi,

I am running stable on a HTPC and I was running 10.1 with no problems the
frame rate was around 28-30 fps.  I updated to 10.2 and now the frame rate
went down to 10-12 fps.

uname -a

FreeBSD mediamaster 10.2-BETA1 FreeBSD 10.2-BETA1 #1 r285364M: Fri Jul 10
20:01:48 PDT 2015     root at FileKeeper:/usr/obj/usr/src/sys/MEDIAMASTER
amd64

Has anyone else seen this?