Network drop packet - speed very slow

[colreg]

Hi all,
I'm sory to say my English so bad.
I’m building firewall – PFSense. The system is running on server HP Proliant DL 380 G6, including a dual gigabit network card.
Version test: 2.0.1-RELEASE and 2.0.2-RELEASE
Service running on: bandwidthd, impector, nut, openvpn, squid
With following system model.
            WAN 1          WAN2
                | (bce0)          |(bce1)
                |                      |
SERVER (em0)–PFSENSE--------DMZ (em1)
                              | (bce2)
                              |
                          LAN

I have 2 problem, please help me to solve that:
At first, when I added 1 interface (nic port remaining – bce3), pfsense will be hung. So I cannot access pfsense, and all the network will drop all packet.
Second, when I access, download file from Internet (bce0, bce1) or copy data from LAN to Server (em0) and DMZ (em1), all OK, with gigabit speed. But when I copy back from Server (em0) and DMZ (em1) to LAN the speed low (approximately 45 ~ 60 Kb).
I try to change MTU and LRO (/etc/sysctl.conf file), there is not different before.
Thanks all,