Nvidia, usb and intel 5000v chipset - pain redefined?

Question

Hello,
I am encountering a very strange problem. My system randomly 'kills' USB-devices:
- keyboard stops responding or behaves wired (like hammering a random button)
- mouse freezes
- usb-sound freezes
- usb-sound produces sometimes noise while moving windows in X around or using the mousewheel
- usb-devices don't get anymore power (LEDs are off)
I've tested every usb-device on other machines - they are fine. It does not seem to be a some kind of electrical problem (using ferrite cores and active usb-hubs). Further I've tested every usb-related setting in the BIOS.
This lasts until the computer is rebooted - plugging out and in again has no effect.
There are no notifications in dmesg like "usb X-Y: USB disconnect, address Z".
Except for once, I've seen something like "xxx PCI Problems?"...what kind of brought me to the idea, that it might could have something to do with the pci-usb-bridge or the graphicscard. I paid more attention to the interrelation of strange USB-behaviour and "graphic-events": moving around windows with compiz-fusion caused massive noise on the usb-sound card. While moving windows without compiz-fusion (e.g. in fluxbox) caused less till none noise.
I reproduced this behaviour on 2.6.24 and 2.6.25 and the following nvidia drivers 169.12, 169.09, 169.07, 173-something and 171.06 within Arch
...and last  but not least, with Gentoo 2008beta1 and Ubuntu 7.10 (whatever versions of drivers/kernel where installed on that two systems). There are no errors when manually loading the module nvidia or within the xorg-logs.
So...next step was to test another graphics-adapter. I borrowed an ATI X1550 PCI card from a friend - no problems at all (though no 3d acceleration), system was stable.
I decided to give the opensource nv-drivers a chance (just to see what happens). And, as you can guess, the same as with the ATI card: system was stable. (This fact might also exclude the mainboard as source of endless pain).
I am currently running this configuration:
Tyan Tempest S5372LC (Intel 5000V Chipset) with up to date BIOS
Geforce FX 5500 256mb, 128bit, PCI
I have, for god's sake, no idea what's wrong. I'm down with my nerves.
Is this a bug? Am I just _too_ blind to see something obvious? Or is this something for the X-Files?
Any idea how this could be solved or what the real problem is, is highly appreciated.
Thanks in advance.
Sorry, if its hard to read - it's quite late here and my English is not that good anyway.

Answer 1

Hello,
according to this list: http://us.download.nvidia.com/XFree86/L … dix-a.html the FX5500 GPU is supported by the unified driver.
Besides Ubuntu installed the unified driver... assuming that its hardware recognition is right.
I could give the legacy driver a shot, although I'm not sure if "legacy" excludes support for never cards.
Regards