David Strom

PCI calvalcade of cards

By David Strom

Just when life on the desktop front was beginning to settle down, along comes more

confusion in the form of more choices. I am referring to the latest crop of Pentium computers

that have Peripheral Component Interconnect (PCI) bus slots and what kinds of network cards

you should put in them.

Like many of you, I suffered mightly through the late 1980's "bus wars" between

Microchannel and the Extended Industry Standard Architectures (EISA). I spent more time

than I care to remember about edge-triggered interrupts, burst mode speeds, and other arcana

when really all I wanted to do was find the best card for the machine and figure out which

bus solved by which bottleneck on my LAN. All that has come back with a vengence it

seems with PCI.

To get a handle on this bus I looked at four Ethernet cards (from Accton, Cogent, Mitron, and

Zynx) on two different Pentium machines: an Ambra desktop that uses a combination of PCI

and ISA slots and a Dell server that mixes PCI and EISA slots. I used both machines as DOS

and Windows clients, and used the Dell as a NetWare server as well. I found that all four

Ethernet cards all delivered some good price-performance, and I recommend the combination

of equipment for the enterprise.

However, I am still left with an uneasy feeling about PCI, and I can't exactly put my finger

on it. I am somewhat uncomfortable with the lack of documentation available for the cards.

Still, I was able to get all four cards working in both machines without too much trouble on

my NetWare network. I had to search high and low for some solid technical information

about PCI, and still feel that I really don't have as much details as I'd like. However, the bus

does seem to work as advertised and my tests proved that it was a faster and cleaner interface

for peripherals than ISA. 

Maybe my lack of comfort has to do with the fact that the mainstream LAN card vendors

(3Com, Intel, SMC, and Eagle) are still not delivering any PCI versions of their adapters.

Maybe it was something disagreeable that I had for dinner. No matter. Let me first tell you a

little about PCI.

PCI had its origins about four years ago, when a group of vendors got together on a

specification called the VESA local bus. The word local refers to the fact that the bus is

located closer to the processor -- "closer" meaning that the data path takes less time and

requires fewer interrupts to get the processor's attention.

This bus was developed quickly so various high-performance graphics cards could come to

market, and the result was a rash of incompatible systems and cards. Intel saw what was

happening and went back to their drawing boards to come up with PCI, a more rigidly

defined standard. It had several advantages such as  procesor independence (while most

Pentiums have PCI slots, you'll see RISC and Motorola machines sporting them sometime

next year as well) and fast data transfer rates about four times that of EISA bus speeds.

PCI cards have few connector pins, making them small and cheap. Ironic, isn't it: one of the

"features" of an EISA card was its huge real-estate compared to other configurations. But that

was 80's thinking. These days, smaller is beautiful.

PCI really shines when it comes to turbocharging video, sometimes delivering very noticeable

performance and redraw gains. However, this is a review of the network cards so let's stick

with that side of things. 

The two machines that I tried had a combination of slots that will be a bit confusing to

explain. In the days of yore (say pre-Pentium), you basically had one bus connector per slot.

Vendors mixed different kinds of slots (32-bit and 16-bit, EISA and ISA, whatever) but the

machines that I've used in the past had a single connector. No more: on the two machines that

I used (and I'm told on lots of others), you have dual connectors installed on some of the

slots. This means lots more flexibility, but also confusing when it comes time to buy a

machine and figure out which slots are free and what kind they are.

Take the Dell server for example. It has six EISA slots and two PCI slots that add up to a

total of seven  slots overall. This is because two of the slots are shared EISA/PCI: while you

can only have a single card occupying the slot, you have a choice of either type to insert. Got

that? None of the seven slots come filled with any cards when you buy the base machine.

Now take the Ambra desktop. It also has seven overall slots split between five ISA slots and

three PCI, so one slot is shared. My unit came with two cards: a PCI video card and an ISA

multimedia card, meaning that five slots were empty.

Those of you that buy alot of equipment over the phone will have to ask questions carefully

before you close the sale: I suggest drawing a mental picture of how many slots and how

many are actually available while you negotiate with the sales representative.

So is it worth the bother? Well, yes and no. The PCI cards I tried were about as fast as my

3Com Etherlink III EISA card, both of which are about 20% faster than the better ISA

Ethernet cards on the market today. However, the PCI cards cost between $150-250

(depending on manufacturer and where you buy them). This is just a little more than the

range for ISA cards and a little less than most of the EISA cards: so you end up getting some

solid price-performance from them when you do all the math. 

The downside has to do more with service, support, and long-term viability of the vendors

than any mechanical or performance considerations. All four of these cards are from relatively

small shops and that makes me nervous when I want to buy them in quantity for my

enterprise. None of the documentation that came with any of the four cards is anything close

to what comes with a 3Com or Novell/Eagle card, and most had more stuff in their README

files on the disk than printed manuals in the box. This is especially disheartening considering

that you are dealing with new territory and would like some guidance. 

No single card stood above the others in my opinion. Zynx was the only one vendor that

included any extended explaination of the PCI bus, and it was more of a marketing brochure

than containing any technical content. Accton [CHECK: TK] was the only vendor of the four

to offer a lifetime warranty on their cards, which is probably the way I'd like to go. Mitron

had two things going for it: the lowest list price among the four ($149) and a nice software

installation routine that the others lacked. 

Cogent and Zynx offered all three Ethernet interfaces (thick, thin, and twisted pair) on their

cards, while the other two offer various combinations of interfaces in different models. That's

a sad state of affairs: you'd like to have the flexibility of all three interfaces on the back. And

both Cogent and Zynx make a four-port card (which I didn't test) to go into servers that seem

to offer lots of promise.

All of the cards offered lots of drivers for various networks, including server drivers for 3.x

and 4.x NetWare, NDIS drivers for various LAN Manager/LAN Server/NT networks, and

packet drivers for various Unix networks. I didn't test much more than the NetWare side, and

I am sure that there will be some tweaking to get your particular configuration to work. This

is where solid documentation could be handy.

Some other detractions: Zynx's card had a jumper to switch between thick and thin/twisted

pair interfaces: set it incorrectly and you won't be able to connect to the network. This is

ridiculous. Accton, Mitron and Cogent all come with firmware that automatically detects

whichever interface was active, which is the way to go. 

Both Cogent and Mitron mention that their cards can only go in PCI slots that have

bus-mastering. I tried to find how to configure both my Dell and Ambra machines for this,

but couldn't find any documentation. However, the cards did work, which was fortunate. 

All four cards were very difficult to physically insert and required lots of elbow grease to get

them in and out of the machines. One time I nearly jammed one card and it took lots of effort

to remove it. My favorite bus for card insertion still is the Microchannel, which is designed

from the start to require very litte force to insert and remove cards.

My bottom line? PCI network cards are faster than ISA, to be sure. But before you rush out

and equip your entire enterprise, make sure you read all the fine print to justify the

price/performance. You might be better off sticking with an EISA card for the short-term,

until the mainstream LAN card vendors enter this market segment or until the others offer

lifetime warranties and better documentation.

Vital Stats

PCI Ethernet Cards from Accton, Cogent, Mitron, and Znyx

ethernet adapters for Peripheral Component Interconnect slots

Cards, cost, and availablitity:

Accton's EN1203 ($249, June), Cogent's EM960C ($249, June), Mitron's LX2100p ($149,

June), and Zynx's Zx312 ($249, February)

Ready for the Enterprise? YES, but don't get too excited about performance gains

Competitive analysis:

UP:  These four are just the beginning of other cards that are shipping for the new PCI bus

slots on many of the latest Pentium desktop and server models. 

DOWN: Performance gains are only about 10-20% beyond the fastest ISA Ethernet cards.

Test bed:

Ambra Pentium PCI desktop running DOS and Windows and a Dell Poweredge SP560 PCI

Pentium server running NetWare 3.11 and 4.x connected via Ethernet.

Vendor info:

Accton Technology Corporation

1962 Zanker Rd.

San Jose, Calif. 95112

408 452-8900

408-452-8988 (fax)

408-452-8811 (faxback)

Cogent Data Technologies, Inc.

PO Box 926

Friday Harbor, Wash. 98250

800 -4-COGENT


206-378-2882 (fax)

internet: support@cogentdata.com

Mitron Inc.

2220 S. Bascom Avenue

Campbell, Calif. 95008




Zynx Advanced Systems Division, Inc.

48501 Warm Springs Blvd #107

Fremont, Calif. 94539



internet: tech@znyx.com


Card                             Accton                  Cogent                         Mitron              


Name                            EN1203                 EM960C                        LX2100p        


Waranty                      lifetime                   two years                     two years            

    three years  

[NOTE: please verify with all vendors to make sure this hasn't changed]

Interfaces                     Coax, TP               Coax, TP, AUI             Coax, TP              

Coax, TP, AUI

NOTE: Both Mitron and Cogent make TP only cards. Cogent and Zynx also make 4-port

cards as well.

Documentation           Minimal                Adequate                     Non-existant        


Installation Swre?       No                         No                                  Yes                 


Click here to return to the previous page

David Strom David Strom Port Washington, NY 11050 USA US TEL: 1 (516) 944-3407