PCI-X 3.3V-only card in PCI 2.3 slot?

[vonoben]

Hi,

I have a Intel PRO/1000 MT Quad Port network card with PCI-X (not PCI-e) interface. The card is keyed as 3.3V-only, in other words it lacks the 5V notch. I would like to use this card on an Atom motherboard with 32-bit PCI 2.3-slots, but those are keyed as 5V for some reason.

PCI2.3 is capable of both 3.3V and 5V signalling, and Intel specify that 3.3V is active on this motherboard.

The keying/notch system is good ofc, but when I'm reading the different standards it seems to me that this card should work in this board if I modify the keying.

Does anyone agree or disagree? Has anyone tried?

Ps. I've seen pictures of motherboards with PCI 3.0, witch are 3.3V only and does not support 5V anymore... they still got that darn 5V notch!

 

[GhislainG]

I haven't tried it, but it should work. You can't insert it into a 5V only slot: http://support.intel.com/support/network/adapter/1000mtquad/sb/cs-009537.htm. Going from a 64 bit bus to a 32 bit bus at a lower frequency will hurt performance.

 

[vonoben]

Yea, I thought so too. Since I'm using a riser card I can rekey the setup there, without modifying the card or the motherboard. I'll tell you if it worked afterwards.

And, yes, running this PCI-X card in a 32-bit slot will ofc hurt performance. The machine will function as a router, based on FreeBSD, and maximum thruput is not prio one, especially since most traffic will route between two interfaces, one on the PCI-card and one internal on the mother board. Maximum thruput will probably be quite good anyway.

The main reason for using this card is to get five ethernet ports all-in-all, FastEthernet (100Mbit) ports would have done the job aswell.

(I do have a couple of 4U dual-cpu servers with PCI-X slots, but I'm trying to reduce my electrical bill.)

 

[vonoben]

No, the system didn't boot with that card inserted. Too bad... I have to replan my router's interface config somehow.

 

[joel-pci]

3.3 V keyed pci motherboards are rare,.
the efika card is one of those, that motherboard
should work with your pci-x card.

there are other motherboards from micetek.com
and http://www.ablyx.com/1173.html

it is a strange matter,. as many FPGA's are 3.3 volts
i/o naturals, and PCI protocol is not that difficult
to implement,. at 66 MHz!!,.

odd,.



Joel



he,..
Ps. I've seen pictures of motherboards with PCI 3.0, witch are 3.3V only and does not support 5V anymore... they still got that darn 5V notch!