R9800np, NF7-S r2, AGP issues

After reformatted and installing Cat4.4 w/out trouble, I was suprised after installing Alcohol 120% I got graphics issues - Windows booted into 640x480 with 4 colours and neither option could be changed...uninstalled Alcohol, but what fixed my problem was when I used ForceASPI 1.8 to update my ASPI layer - Windows still booted into 640x480 with 4 colours afterwards, but this time options could be changed successfully (I've since reinstalled Alcohol120% w/out issue).

The problem then resurfaced once I overclocked my PC (check sig, was running @ stock during reformat). So, after reverting to Cat4.3 (which fixed the colour issue), whenever I boot into Windows the resolution is STILL set to 640x480, but this again can be changed. Problem also occurs with Catalyst 4.5

Very confusing problem, doubt it's the overclock since Cat4.3 runs fine (so to speak) and is "Prime" stable. Did have similar issues when Cat4.4's were first released, but I didn't think much of it at the time. The problem first surfaced after I had updated my BIOS to d21, and I have a sneaking suspicion it's related to IRQ allocation for USB because Windows kept on asking me for an updated driver (which is weird, because SP1 includes USB2.0 support - USB had exclamation mark in "device manager")

This leads me to some research, where I've found some articles pointing to IRQ sharing, and the way WinXP uses ACPI/APIC to give additional IRQ's (I'm currently using ACPI). In particular, some point out that the PCI slot next to the AGP one is often hard-wired to share an IRQ with it.

Have I possible overlooked some conflict? Any troubleshooting suggestions? Thanks in advance

Using WinXP w/SP1, Catalyst 4.3, nForce Unified 4.24.

Just checked, R9800 on its own IRQ (19), only items sharing IRQ's are:

IRQ20 - Standard Enhanced PCI to USB host controller
- NVIDIA(R) nForce(TM) Audio Codec interface
IRQ21 - Standard OpenHCD USB Host Controller
- NVIDIA nForce Networking controller
- OHCI Compliant IEEE 1394 Host Controller
IRQ22 - Standard OpenHCD USB Host Controller
- NVIDIA(R) nForce(TM) MCP Audio Processing Unit

No PCI device within 2 slots of the AGP, the plot thickens!

*BUMP*
anyone?!

I received a reply from ATi, and one of their suggestions was:
(check) your AGP chipset drivers are the latest

How can I go about updating my AGP chipset drivers? And does having an anti-virus program like NAV open while installing really affect the installation?!

Your problem sounds worse than the one I had. When I installed my 9800pro it was glitchy and I couldn't fix the problem, although nothing like you are describing.

To make a long story short, I ended up flashing the latest bios (on the NF7-S), clearing the CMOS, loading failsafe defaults, loading windows, (re)installing the latest nForce drivers, and rebooting and resetting my original bios settings. I also removed the ati drivers and loaded the 4.5 Omega drivers.

This seemed to solve my problems. Good luck!