Re: AMD64, Tyan K8W, Geforce 5700 = black screen
Update and summary:
Hardware: Tyan K8W s2885 and Aopen Aeolus Geforce FX 5700
Linux: Works great in PCI mode. Black screen and 100% CPU utilization by X process when AGP is used. Monitor never enters powersave mode.
Windows XP: Works great in PCI mode. Enable AGP driver and you get a black screen that eventually the monitor goes into powersave mode. I have even attempted to update to the latest drivers available and the result is the same.
Different Card: Using a Geforce FX 5700 Ultra everything works fine, including in AGP mode.
Conclusions: Motherboard is fine (different card works great). Configuration is fine (no changes were needed to get other card working). Because the card I'm having issues with works in PCI mode perfectly fine, I do not believe the card is at fault. If the card was faulty, I would expect to have other symptoms - card not working at all, visual issues etc. Although the card is running in 'pci mode' when it works, it's probably safe to assume that all the circuitry is working fine. It just won't work in this motherboard.
Unfortunately this is as far as I can take it without someone from nvidia getting involved and providing additional software testing/debugging that can be performed. I do not have any other boxes with AGP slots, and neither do my friends (they have the same box, or older non-agp boxes).
This is a big disappointment in an otherwise excellent box.