From: "Kevin Weaver" :Sent: Sunday, September 17, 2000 6:43 PM
Subject: Re: [PCBUILD] IRQ Headache +A


> After much research on the Dell site, I have found that the IRQ's are
> assigned to the slots with no way to change them. So this leads to a new
> question. I have three available PCI slots and three PCI cards. Currently
> the USB and the NIC share IRQ 10 and the voodoo3 graphics card is alone
with
> IRQ 3. Will the graphics card work if sharing IRQ 10 with the NIC so that
> the USB card can have IRQ 3 all to itself?
>
> Kevin Weaver
>

Kevin,

The USB controller on all of my computers shares an IRQ with some other
device but most of my NIC's do not share an IRQ.  I am curious why you were
told the USB controller could not share an IRQ, as all of my own systems and
all of the systems I have built the USB controller has been able to share an
IRQ.  Some graphics controllers (GeForce), and NICs have been the only
adapters that I have had to install not sharing an IRQ.  I would be more apt
to switch the video card and the NIC, so that the NIC has an IRQ by itself.
Does the Dell site tell you which PCI slot has which IRQ?  The AGP slot, all
PCI slots in the system and the USB controller share 4 IRQ's.  Most likely
the AGP port and one of the PCI slots will share an IRQ,  two of your PCI
slots should not share an IRQ and if you have 5 PCI slots then the last two
PCI slots also share an IRQ, thrown into this mix the USB controller shares
an IRQ with one of the PCI slots or a group of PCI slots.  If you are able
to determine how the AGP slot, PCI slots and the USB controller share IRQ's
and which IRQ's are assigned by Dell to each of these groups you should be
able to work out a placement.  Most motherboard manufacturers give you all
of this information in the motherboard manual, so when you install adapters
into the slots you can assign IRQ's either in the BIOS or through placement.

Mary Wolden

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