IRQ sharing problems!!!

Discussion in 'BIOS Optimization Guide (BOG)' started by johna156, Dec 30, 2002.

  1. johna156

    johna156 Newbie

    Ok ,so windows and generally the latest m/bs are "optimised" to use the irqs in the best possible way, and according to QDI forum techs , irq sharing has no effect on gpu's performance.

    I don't know for you people ,but my comp which is a P4 1,8 Northwood with 512MB RIMMs on a QDI Platinix 4N and a Creative geforce 3Ti500 ,(os:winME), after i had installed windows ,had messed up the irq sharing.

    The gpu had the same irq with almost 10 (!!!!) other devices, such as modem, soundcard, controllers etc. You can imagine that when I tried to run 3Dmark it was pretty much ok ,but when I tried playing a game (with sound enabled ofcourse),the performance was poorer than the one i had with my previous setup (P3 600 ,geforce 256).
    I tried to see what's going on with directx diag. and that's when I found out that all the tests (spining cube ,bouncing box etc.) were running like in slow motion!!!!!
    So I went to the Bios to see if I could enable "assign irq to vga" ,which is an option on all the other "older" m/b i ever had ... but no sign of this option.
    Then I posted my problem to QDI forum and they told me that irq sharing has no effect on graphics performance and that they could prove it to me trough benchmark's figures they had ... HELLO???? I never said I had a problem with benchmarks but with games!! You see benchmarks don't use sound ,input controllers ,modems etc.

    All I could do was try to get the irq sharing manually ... NO SIR!!! No matter what I did ,my Geforce was always sharing the same irq with either the modem or the soundcard ,(I even tried to change the modem and soundcard's slots).
    If I was succeeding not having the modem or soundcard at the same irq with my geforce ,then it had the same irq with the serial bus controller which also messed up the gpu's performance !!!!
    Now the best I have done is to disable a serial bus controller ,so that my geforce (and an ACPI irq holder which has no effect on the gpu's performance), uses the irq 11 and everything simply works perfect!!
    Now don't ask me if I tried just to re-install windows 'cause I did and nothing changed and don't tell me to update the m/b bios or download the latest chipset drivers ... I have already done it.
    I'm not a professional but I do know a little about computers (my first comp was a CPC 6128) and I can't find any other solution or haven't thought any yet ...
    Perhaps a m/b tweak utility will do the trick but is it safe?? I don't know any m/b tweak utility so if anyone does ,just let me know ...
    Oh btw ,does anyone knows if platinix 4N will work with a gf4ti 4600? (I read in forums that gf4Ti series needs 1,5volt power or with more it gets toasted and I don't know what voltage my m/b is capable of) .
    Also is it safe to enable through tweak utilities the sideband addressing option?? (there is no such option in the bios menu). Thanx in advance and sorry for the biiiiig post :oops:
  2. Adrian Wong

    Adrian Wong Da Boss Staff Member

    Hello johna156,

    First of all, take a deep breath and relax. :)

    Now, you appear to have a new motherboard. Please check the BIOS for APIC Function (NOT ACPI Function). Make sure it's enabled. For more details on APIC Function, click here.

    If that doesn't give each of your device its own IRQ, then you will have to REINSTALL Windows XP. Before you start saying, "I already did that!", try reinstalling Windows XP with ACPI disabled. That's both in the BIOS as well as during the installation process.

    Go to your BIOS and check if ACPI Function (or a similar BIOS option) is available. If it is, disable it. During Windows XP installation, make sure you do NOT set your system as an ACPI-compliant computer. I can't remember the exact type of system you should select but I think it's "Non-ACPI Computer". Something to that effect.

    Once you do that, Windows XP will install with ACPI disabled. That will basically leave IRQ management to the BIOS. You will then have control over your IRQs.

    As for the GeForce 4 Ti, it's available as either AGP4X and AGP8X cards. AGP4X requires 1.5V while AGP8X requires only 0.8V. But there's really not much need to worry about the voltages. Just check your motherboard's specs. If it supports AGP4X, then it can provide the 1.5V required by AGP4X cards. The same goes for AGP8X support.

    Sidebanding support must be enabled on both the motherboard as well as the graphics card for it to work. Sideband support used to be disabled in the older motherboards + graphics cards because there was some compatibility issues. However, it's really not the case these days. Sideband support should be enabled by default in both motherboard and graphics card these days.

    Hope that helps you some! :)
  3. johna156

    johna156 Newbie

    Thanx a lot for the hints ,I'll try them out but ,my OS is WINME not xp . Does this make any difference?
    Also there is no sideband addressing option in the bios menu ,there isn't one for fast writes too , but fast writes is enabled (as far as I can tell by the system info in 3dMark2001!!!).
    So that's why I'm asking if it is safe to enable s.a. through a tweak utility,
    because maybe my m/b doesn't support this option...Oh and don't tell me to ask the qdi forum ,cause I've posted them these questions over 5 times and they just don't answer...(bastards!)
    Btw, i read few of the guides you have for the options in bios menus and in my bios menu there is no option PnP OS yes - no. Is this normal??

    Ok ,I've checked my bios menu and there's no option APCI enabled/disabled, the only option is ACPI function enabled/disabled and ACPI suspend type S1(pos)/S3(str) and I don't know what the second one is...

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