66 MHz NIC?

Are there any 100 Base T network cards that run at 66 MHz? I ask because I am building a new file server and I want the NIC to be on the 66 MHz PCI bus, to avoid latency issues associated with the 33 MHz PCI bus, but I don't want it running at 33 MHz, because that would slow down the bus and I have a 66 MHz SCSI RAID card in the other 66 MHz slot.

This is all on a 760MPX motherboard, BTW.

I believe there are Gigabit Ethernet cards that run off 66 MHz, but are they backwards compatible with 100 Base T networks?





I know this is the SMP forum and not Networking, but I figured you SMP folks probably have a lot more relevant experiece with this issue.


Thanks.

A short search for a mere 100 base-TX NIC with 66 MHz operation didn't turn up any single port candidates, and four port cards are notoriously expensive. But that's fine, as virtually all gigabit NICs also do 100, and probably most are 10/100/1000 (just in case you have dinosaur on your network).

Many gigabit cards with "server" in their names are both 64-bit and 66 MHz, though making sure is of course recommended. The Linksys EG1064 and Intel PRO/1000T are such cards.

The 3Com 3C996B-T and Intel PRO/1000XT additionally support PCI-X, so they should not only work, but also be ready when you upgrade to a SledgeHammer system with PCI-X slots. =)

All of these cards are 10/100/1000 capable... and I've never used any of them. I just do research.

Could you explain the latency issues with the 32-bit bus? Does it present a big enough issue that there would be a noticable increase between running the NIC on either bus?

And what SCSI card are you using?

Thanks a lot, man. That was exactly what I needed to know. Best of all, the Intel Gigabit card is only about $50, supports 33/66/100/133 MHz and is 32 or 64 bit.

According to the Intel website, which we would assume to be the ultimate authority on such matters, I made a mistake in my network card review.

Both the Pro/1000T and Pro/1000MT (part numbers PWLA8390T and PWLA8390MT, respectively, gotta love consistency) are 32-bit PCI, but they are 66 MHz.

The Pro/1000XT (PWLA8490XT) is 64-bit and will go all the way up to 133 MHz.

I'd be *very* impressed if you managed to dig up an XT for 50$, though Pricewatch indicates that MTs can be had for about that much. An MT board may not be 64-bit or support mega-fast PCI-X speeds, but it does admittedly meet your requirement of not slowing the clock speed of your MPX board's 66 MHz PCI bus.


On the subject of inefficiency of the 32-bit 33 MHz slots on 760MPX motherboards, we have testimony from forum members that (for example) a gigabit NIC only thumped out 150 Mb/s in such a slot, and another situation with a video card, both listed in the thread about 64-bit PCI slots.

http://forum.oc-forums.com/vb/showthread.php?s=&threadid=119413

Which sounds bad, but 150 Mb/s is still more than 100 Mb ethernet supports. That said, I don't see why there couldn't be latency issues as well, if cmcquistion was referring to something other than the oddly low transfer rates.

My pet theory about this is still that the 32-bit PCI bus on 760MPX is suboptimal because it's a secondary bus attached as an offshoot of the 64-bit 66 MHz primary bus. It's a fact that the 32-bit slots are on a secondary bus; my using this fact as a scapegoat is mere speculation.

I'm using an Adaptec 2100S SCSI RAID card. I'm not 100% sure that it is a true 66MHz card. It has the cutout for the 66MHz slot, and during the bootup, it says that it is increasing latency from 20h to 40h (which I believe is directly proportional to the bus speed it is operating on, currently 33MHz). On Adaptec's website, of course, they claim it is only 33MHz, 32 bit. Their website leaves something to be desired, however. I'm going to call them tomorrow and see if I can get more reliable information.


You were right. The adapter I was looking at was the server version of the Intel Pro 1000 MT. The one I found for sale was the desktop version, which is 33MHz/32bit or 66MHz/32 bit. Still fine for me.

I have Intel 1000xTL (PCIX i.e. 133Mhz/64bit) in my new IWill MPX2 in a 64bit slot. It runs great, no problems with my FSB at 145 but I haven't gotten round to serious overclocking yet.

Be carefull with gigabit over copper. I think you maximum run length is around 3 meters. Or 1 leg, 3 feet and 16 eigths of a finger if you live in the US

You're wrong. Provided you use Cat 5E (not regular Cat 5e), your maximum cable length is 295 feet.

Wow, it has progressed a lot since I last looked at it

Many of the 3Com NIC's support 64bit/33Mhz. Look for the cards with two notches on the connector. They should work fine in the slot and will be far cheaper than a server NIC.

I already ordered the Intel Pro 1000 MT. It is 33/66 MHz and 32 bit. It a full 10/100/1000 card. I installed it and it has been running great so far. Just on 100 Base T, though. I don't have the gigabit uplink for my switch.

I already ordered the Intel Pro 1000 MT. It is 33/66 MHz and 32 bit. It a full 10/100/1000 card. I installed it and it has been running great so far.

Click to expand...

Well, good-- I'd hate to think that I advocated a bad card. I kinda want a cool NIC, but I don't have a good excuse to, as my TigerMP doesn't have the dreaded Secondary PCI Bus Issue. It also doesn't do 66 MHz, so I'd have to buy a 64-bit card in order to be Neat-O...

On that subject, it was great of you to quantify the Secondary PCI Bus Issue over in the 66 MHz FireWire thread. http://forum.oc-forums.com/vb/showthread.php?s=&threadid=126282

Many of the 3Com NIC's support 64bit/33Mhz. Look for the cards with two notches on the connector. They should work fine in the slot and will be far cheaper than a server NIC.

Click to expand...

Intrigued, I scoured the 3Com website, and they divided their NICs into two categories: A) 100baseTX for desktops, and B) server cards.

None of the desktop cards have any kind of fancy PCI (I checked the data sheets for every one listed). While several server cards have fancy PCI, they also have server prices.