Here's a photo of what I don't understand. Why share IRQ's when IRQ 12 is free?

In the BIOS, I've reserved IRQ 5 and 10 for ISA (ISA sound and ethernet cards), but IRQ 12 is left as "Auto".

From what i've read IRQ12 was used by PS/2 mouse, maybe its holding it just in case.
Have you disabled PS/2 port on BIOS?.. tried using a serial mouse?

Either way PCI should not have problems sharing IRQs, at least that's the theory.

This system does not have a PS/2 mouse header. It does have solder pads for a PS/2 mouse connector, but the wiring on the PCB for PS/2 mouse is not connected for PS/2 operation - it is connected only for AT keyboard operation. And Windows lists IRQ 12 as free. Since 'im using a BUS mouse on IRQ 2/9, I'd like to have IRQ 12 used for other things. In the past, I've run into issues like this in Win95 and was wondering if there was a way to force an IRQ upon a device.

How many PCI slots?
In the old ISA/PCI setup, a maximum of 4 IRQs are released from ISA to PCI use, and they roll as INTA to INTD across the slots - some slots will always share - if there are more than 4. If there are less than 4 IRQs in the pool, sharing is more likely and harder to predict.

Looks like there are 3 more free, but maybe release another by disabling a COM or LPT if unused, then move one of the cards to a different slot - if they are in slots that share the same allocation of IRQ, nothing in software can separate them.

The theory is that level triggered PCI IRQ can be shared, the practice is that some cards don't agree too well with it, Promise being one of them.

Did you try forcing the IRQ from Device Manager?

Just uncheck "Use Automatic Settings" then switch to configuration 0001, then click the "Change Setting" box and change it to what you want and hit OK.

Matth79 -

The NexGen has 3 PCI slots and 4 ISA (with one of these 4 shared w/PCI).

IRQ 5 now uses the sound card, IRQ 10 now uses the ethernet card, IRQ 2/9 is with the bus mouse, and IRQ 7 is for the LPT port. I plan on doing some parallel port testing, so I don't want to open up IRQ 7. Same for IRQ 3 & 4.

All I want to do is get the Promise Ultra100 or the Matrox G200 to use IRQ 12.

You are saying that the system can only allocate 4 IRQ's to PCI? That's IRQ 14 & 15 for the onboard IDE, both of which I'm using, and IRQ 11 for the Matrox & Promise. That means I should still be able to have one more IRQ for PCI devices? How about IRQ 12 instead of sharing IRQ 11?

I suspect that the system insists that IRQ 12 be for ISA cards. I say this because when I insert an ISA SCSI card, it insists on using IRQ 12 over any other IRQ I tell the SCSI BIOS to use.

wiretap -

Yes, I have already tried what you suggest as my very first course of action upon discovery of the problem. When unchecking "use automatic settings", there is no other configuration besides Basic 0000. If I click an IRQ and click "change setting", I receive an error saying that these values cannot be modified.