FreeBSD 7.2 vs Linux in routing performance

[Sebastian Hyrwall]

Hi

I have to identical x86 routers with the following specifications,

hw.model: Intel(R) Atom(TM) CPU  330   @ 1.60GHz
hw.physmem: 2132996096
hw.usermem: 1787252736
hw.realmem: 2146041856
2x re0: <RealTek 8168/8168B/8168C/8168CP/8168D/8111B/8111C/8111CP PCIe 
Gigabit Ethernet> port 0xd800-0xd8ff mem 
0xfeaff000-0xfeafffff,0xfdef0000-0xfdefffff irq 16 at device 0.0 on pci2

I know it's not really the best equipment to use in gbit-enviroments but 
that is irrelevant here.

One of these runs FreeBSD 7.2 (R-p4) and the other Linux 2.6.31.5.

Without pf/iptables loaded the FreeBSD-server maxes out at 35MB/s when 
it comes to forwarding between the two NICs (simple http-transfer used 
for testing).
The Linux-server pushes 90-100MB/s between the NICs with the same test. 
Both servers are connected the same way to the network (I swap them 
between the testing).

Any suggestions on where the gigantic performance loss might be and how 
to fix it?

I intend to switch FreeBSD 8 in the coming month and maybe that will fix 
the problem but I am hoping it's also fixable in 7.2.

Sincerely,
Sebastian  H.