PfSense 1.2.3 and gaming, 50 clients.
I've built a router with pfSense 1.2.3.
4Gb DDR2 @ 800Mhz
Internal + Intel 4-port + Intel 1port
MultiWAN, loadbalancing over 5 ports/ip:s.
So, this machine will act as a router on a LAN with 50 klients playing Battlefield 2, 3 BC2, SC2, CS, Wow and so on..
I played BF3 yesterday, and after enabling UPnP it worked perfect. (Except one loss of connection for a few seconds).
Is there some things I have to do to make it work better?
Rules, NAT and so on?
I would suggest you look at the traffic shaper which should help. I would also recommend you move to the newest version of PFsense, 2.0 which has many more features.