Motherboard ethernet vs PCI-x card

[HGBCadmin]

I'm recycling an old server as a firewall.  Its an HL DL580 g3. 4GBram, scsi disks.
The quick specs are here:
http://h18004.www1.hp.com/products/quickspecs/12195_na/12195_na.HTML

My question is if I should expect better throughput from the built-in ethernet ports on the motherboard or from a PCI-x card, something like this:
http://www.intel.com/content/www/us/en/network-adapters/gigabit-network-adapters/pro-1000-mt-dp.html  which I have available.
With it being server grade kit I'm wondering if there's much if anything to be gained.

I am looking for a 1 wan 1 lan config for now moving to a 2 wan 1 lan config.
The WAN is 65MB BT Fibre.  There are 10 users and some streaming video requirements.

Just wondering what you would do?

andy

[stephenw10]

Whether they are on-board or not the NICs must be connected via some bus or other. Looking at the spec sheet:

Network Controller:  Embedded NC7782 PCI-X Gigabit Server Adapter

It appears the on-board ethernet is also PCI-X. It then comes down to the bus speed as to whether or not it would be faster.
I would say it's not much different.

The NC7782 is a Broadcom based NIC which are generally well thought of under FreeBSD, second only to Intel.

Steve