PCI in PCI-X slot?

[EniGmA1987]

I did some reading and heard that PCI-X slots are backwards compatible with PCI, but the lowest speed they can go is 66MHz. PCI specification 2.2 allows standard 32-bit 33MHz PCI cards to run at up to 66MHz


PCI-X is a high-performance variant of 64-bit PCI designed for servers. PCI-X adapters and slots are backward-compatible with 32-bit PCI slots and adapters.


PCI 2.1, released on June 1, 1995, allows for 66 MHz signalling at 3.3 volt signal voltage (peak transfer rate of 533MB/s), but at 33 MHz both 5 volt and 3.3 volt signal voltages are still allowed. It also added transaction latency limits to the specification.[7]
PCI 2.2 Power rails to provide 3.3 volt supply voltage are now mandatory.


However, in a new computer I am building whenever I try to stick a PCI add in card (for USB ports) in any of the PCI-X slots then the computer will not power on at all. The PCI add-in card says it is fully PCI 2.2 compliant so it would have to support signaling at 66MHz.

I press the button and the power flickers on for a split second and then acts like it has no power and the PSU is turned off. I have to take the card out, turn off the PSU, turn the PSU back on, and then power on the computer to get it up and running again.

It almost seems like the motherboard is being shorted out to the case when a card is installed, but I really dont see how that would happen. The card is a little tight going in to the PCI-X slot, but I have done plenty of other computers that were just as tight or even more so. And yes I know how to stick a PCI card in :P And yes I know all PCI-X slots on the same bus get down clocked to the slowest card, I only have a single card going in them so it doesn't matter.


Does anyone have any ideas?

[Serra]

Complete Guesses:
1. BIOS option?
2. PCI card manufacturer lied or took advantage of some grey area in the PCI 2.2 guidelines
3. The PCI card itself just doesn't work

[STEvil]

might need to adjust the bios settings of the slot before putting the card in but yeah, sounds broken.

[EniGmA1987]

I have 2 of the same card because I was going to have them both on the PCI-X slots, I can use one by itself in the single PCI slot on the motherboard and it works fine. I tested both cards and they both work fine. So it is either some setting I have to do in the bios, the PCI-X chipset isn't working properly, or the card's chipset isn't made to spec. It uses an NEC chipset, I cant remember the numbers but I can look at it later to get the actual model of the chip.

I haven't seen any PCI-X options in the bios, it is a Tyan S2932G2NR-E motherboard if anyone happens to know that board and has any suggestions then please post :)
The -SI version was sold out the day I was buying the parts so I had to get the -E version :/

[EniGmA1987]

Chip is an NEC 07201010GJ

EDIT: The PCI-X chipset is also an NEC.

[Serra]

Well that is pretty damning. NEC making both chips... one would really expect it to work.

At this point, I think your best option may be to call Tyan. :shrug:

[tiro_uspsss]

are there *any other cards in the system?

are there any inbuilt extras on the mobo? example: any Silicon Image SATA/SAS controllers - or any SCSI controllers by other companies?

[tiro_uspsss]

newegg says:

NEC nPD720400
SMSC DME5017
LSI 1068E

as other chipsets...
dunno how accurate that is..

the LSI SAS controller - do u have that? I doubt it would play a role as it is PCI-E - but if u wanna fiddle around, disable it, see if it works then..
I having a complete stab in the dark here: anything that is running of PCI or PCI-X *could affect it - this could incl. the LAN chips etc.. disable everything, do a thorough search thru BIOS for any PCI/PCI-X related settings.. then test again :shrug:

thats all I can think of

[EniGmA1987]

No PCI-X related options in bios at all :'(
No SAS controller, that is on the more expensive version.

I tried unplugging all other cards and just put a single PCI card in one of the slots, tried both the channel A slot and one of the channel B slots, neither all the system to power on. I dont know, it just seems really weird to me. Normally it would just not post, but this doesnt even power on. Like something is being shorted out. The only explanation I can think of is the traces on the card itself are somehow routed that one of the voltage pins is connected to one of the ground pins. Nothing else makes any sense to me.