NIC to avoid...?

Martin Siegert siegert at
Tue Aug 28 11:42:30 PDT 2001

On Tue, Aug 28, 2001 at 11:32:38AM -0400, Michael Sowka wrote:
> Can someone please clarify something for me... I was just about to fill 
> out a PO for our upcoming 16 node cluster when I stumbled upon this info 
> concerning the 10/100 NIC card (read: that's the card I plan on using :( ):
> What exactly does that mean... should I stay away from this NIC... and 
> what NIC do you guys recommend?! Performance is the key as we're blowing 
> a fair amount of money and a Cisco Catalist 3500 Switch....

With respect to the NIC:
I believe you are refering to the following section on the web site above:

<quote from>
Problem Hardware:

- 3Com 3C905CX-TXNM Ethernet Adapter
There are two problems associated with using the 3C905CX-TXNM adapter. 
1. The adapter does not support network booting using PXE. 
2. The network boot kernel provided with LUI contains a driver (3c59x) that
   does not properly initialize this adapter, rendering it unable to receive

It is suggested that you avoid this adapter completely if at all

Firstly, if you really want to know whether there are problems with that
card you should post your question to the linux-vortex mailing list,
Secondly: I don't know anything about OSCAR and why they have problems with
3C905C cards, but if I had to choose between OSCAR and 3c905 cards I would
choose the 3c905 cards: In all my benchmarks that I have done on 100baseT NICs
the 3c905 cards with the 3c59x driver showed the best results. I just ordered
a 70 node beowulf cluster with two on board 3c920 NICs and two 3c905CX-TXM NICs
in each node. All of them use the 3c59x driver. On my test system netpipe
(NPtcp) shows a latency of 43us and a bandwith of 89.8 Mbit/s between two
3c905C cards and 52us / 269.2 Mbit/s latency/bandwidth using 3 NICs on
each node in a channel bonded configuration. I don't think that you can do
much better than that. (There is another benefit with 3c905c cards: they
are so slim that you can plug them directly into the PCI slots of the
motherboard even in a 2U case - no need for a riser card).

With respect to the quotes from the OSCAR web site:
1) I do not know whether/why the 3c905CX-TXNM doesn't support PXE - I don't
   use PXE.
2) This is a strange remark: Why don't they upgrade the kernel instead?
   AFAIK there are no issues with the 3c59x driver in kernels 2.2.19 and
   later including the 2.4.x kernels.

In short: With respect to the 3c905c cards in general I can't agree with
the suggestion from the OSCAR site at all. With respect to 3c905c cards
working with OSCAR specifically I can't comment - I'm not using OSCAR.


Martin Siegert
Academic Computing Services                        phone: (604) 291-4691
Simon Fraser University                            fax:   (604) 291-4242
Burnaby, British Columbia                          email: siegert at
Canada  V5A 1S6

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