4 core Opteron performance

[ke han]

I realize this is a bit open-ended.  But I need some advice anyway as  
I need to make a final decision on using FreeBSD 6.1 on a production  
server.
I have a new Sun x4100 server.  2 x dual core Opterons with 8 GB  
RAM.  I need to run MySQL 5, a single threaded HTTP server, and a few  
other single threaded daemons.
This server will have lots of long living sockets for one of the  
single threaded servers.  Other than that, its not outside normal  
usage bounds.
I would like feedback on overall performance from anyone who has used  
FreeBSD 6.1 with hardware similar to this.  I'm not a guy who cares  
about getting the last 10% of performance out of a server.  I am  
happy to trade performance for maintainability and a little peace of  
mind.

btw, I'm not tried to start another "FreeBSD has poor SMP" flame-fest.

any thoughts?
  thanks, ke han