Odd performance with FreeBSD 4.10 and Compaq 317453-001 dual ethernet NIC

[J. Seth Henry]

Hello,
I recently decided to swap out the 3Com 3C905-TXM board in my router for a 
dual port Compaq NC3122 (317453-001) dual port NIC so I could avoid using the 
built-in NIC (the Intel ICH2 integrated fxp device) Ironically, I was told 
that this board would perform well for this application.

The board has a Intel/DEC 21152 PCI bridge, and two Intel S82558B ethernet 
controllers - all of which are found and initialized. The board shows up as 
fxp0 and fxp1 under pcib1. Both ports indicate a link to the switch, and show 
activity. 

The problem is that performance for both ports is, shall we say, extremely 
lacking. I will see normal performance for a few seconds, then the board will 
"disappear" for several seconds, then "reappear". In some cases, the board 
will quit responding so long that services will time out. When I ssh into the 
router through one of the ports on this board, I can see the remote end stop 
responding to my typing in mid-stream.

Other than the fact that remote hosts are having a devil of a time talking to 
the router when this board is used, there is nothing in the logs to indicate 
trouble, and the machine is stable.  The original NIC works fine - and I use 
it to log in and halt the box when I am testing.

Is this just a bad board, or is something else going on? If anything, I would 
suspect the bridge chip, as both ports exhibit this behavior.

Thanks!
- Seth Henry