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View Full Version : I don't get it.....



Jstyr
06-09-03, 09:42 PM
Why are there only 15 channels for IRQ's??? I mean come on...some of the dumbest things get their own channel and now my sound card and NIC and USB controllers have to share an IRQ!!??

SLK
06-09-03, 10:03 PM
APIC probibly disabled

Brk
06-09-03, 10:38 PM
You need to enable APIC in your BIOS, and set the MPS Revision to 1.4 if there is an option to do so.

Jstyr
06-09-03, 11:07 PM
Originally posted by Burke
You need to enable APIC in your BIOS, and set the MPS Revision to 1.4 if there is an option to do so.

Ahhhh. I learn something new. And it seems I'll have to do a reinstall to enable APIC mode :mad:

/shambles off with eyes glazed over.............

SLK
06-10-03, 09:53 PM
Yep that would be correct...


You don't need 22 Irqs anyways. Those are like "Virtual IRQs" and they are not real IRQs they run from the 15 you already have. It may cause more of a problem if you enable APIC. Its just Billy's way of saying that there are no worries with Microsoft:rolleyes:


If you are having no problems then I would just leave APIC disabled.

Brk
06-10-03, 10:09 PM
Disabling APIC will hinder your ability to use the extended number of IRQs to get each device on its own IRQ, which is highly recommended for stability.

A_old
06-11-03, 12:49 AM
The only shared IRQ i have is my sound and usb..doesn't make a difference. yes, it's all great in theory..but realistically, on newer boards apic..will take care of it fine w/ newer os's.. and u will not have many conflicts..unless you're a pci slot w-hore--and most of the time stability and speed aren't an issue even then.

older mobos share more...older versions of acpi..and tend to be a little more quirky--but even on an old kt133a platform..with shared irqs (usually 9 or 11 is the big one for some reason).. i had no issues what so ever and never went through the headache of reinstalling..and this is on an athlon system too...intel platforms are a little easier to setup successfully..

i must admit the only thing i have against amd right now is the lack of a head spreader on the axp and that they aren't making their own top of the line chipset like intel is...at least one of those will change with hammer..and the chipset may also change..altho i'll probably be on a via or nvidia hammer chipset personally..that is if my next purchase isn't a p4c. i need to wait and see how it pans out and what the price/performance ratios are.

but anyway, no one has answered your question.. it's probably because this was all founded on early x86 standards and no one bothered to change it since there was never a need..and when the need came, a work around was made to preserve backward compatibility..

Amro

Jstyr
06-11-03, 03:34 AM
Thanks for the run down Amro. The only reason I'm considering the reformat is that I'm having some issues with my video card. While the video card actually has it's own IRQ I did notice a strange decrease in performance when I updated my soundcard drivers.

It might just be time to start over with a clean slate.

YeOldeStonecat
06-11-03, 06:40 AM
Originally posted by Jstyr
Why are there only 15 channels for IRQ's??? I mean come on...some of the dumbest things get their own channel and now my sound card and NIC and USB controllers have to share an IRQ!!??

That's the way it was back then...DOS/Win9X only worked, and still only works, with 8259 PIC. 640k RAM was supposed to be all we ever needed also. But in reality....things need to evolve, and eventually something comes along to replace it. APIC came along in multiprocessor boards a while ago, and only works with Windows NT based OS's. With 2K and XP becoming common place in the home market, you also now see it in single processor boards. It's nice to have 24 - 64 IRQ's available.

On legacy BIOS systems, what can help with the limited IRQ's is disabling legacy devices you don't need. This works better on Intel systems than AMD systems I've noticed. Things you most likely aren't using....that LPT1 parallel port (IRQ 7), those old 9 pin serial COM ports 1 & 2 (IRQ 4 and 3), if you use a RAID controller, disable the onboard IDE if you're not using one (IRQ...uhm...13 or 14...I forget which one). When you disable these in BIOS, it will free up those IRQ's they were using, and often devices that were once sharing an IRQ will not take one of these newly freed up ones.

Also, most motherboards will share an IRQ between the top (first) PCI slot, and the AGP video card...so it's not a good idea to use that top PCI slot. Also some motherboards will have IRQ sharing on their bottom PCI slot also.

Yet another way around this...say you freed up IRQ 3...and you're trying to get your NIC to take that IRQ 3..but no matter what you do, it still tries to get a shared IRQ with something else. Well...some motherboards will allow you to assign a specific PCI slot a specific IRQ. So if you disabled COM2 which freed up IRQ 3, and you want your NIC to take IRQ 3....go into the BIOS, and assign the PCI slot that your NIC is in to IRQ 3.

You generally don't want video, NIC, or sound, to share an IRQ.

A_old
06-11-03, 10:39 PM
Originally posted by Jstyr
Thanks for the run down Amro. The only reason I'm considering the reformat is that I'm having some issues with my video card. While the video card actually has it's own IRQ I did notice a strange decrease in performance when I updated my soundcard drivers.

It might just be time to start over with a clean slate.

My advice here is don't fix what isn't broken. Your soundcard is a decent one but there are known issues with creatives and many chipsets *cough* via *cough*..so i suggest rolling back to the old driver if it worked well.. i've had major issues with their drivers on brand new boards..even an nforce2 and audigy 2 combo gave me hell for a customer (he's actually an SG lurker sometimes).

Amro