IDE UDMA/ATA Suckage, or something else?

I have had numerous problems with several different motherboards, and so have some colleagues of mine. The motherboards are Asus A7V133 (newer and older revisions), Tyan K7 Thunder, and Asus A7M266. They all have NVidia AGP video cards and they vary from Duron 750MHz to Athlon Thunderbird 1.4GHz, to Athlon MP 1.2GHz CPUs. Chipsets are VIA, AMD760, AMD761, and AMD760MP.

In every case they all exhibit frequent lockups, often to the point that remote connections fail requiring a reset, while running intense 3D software, and occasional lockups when running intensive X applications. Note that not all these systems have been using the NVidia 1.0-1251 3D driver - at times they were just using the nv driver provided by XFree86
- and they have been run in multiple AGP configurations from 1x - 4x, FW on and off, and in PCI only mode.

Currently, I am running a 2.4.7-ac10 SMP debug kernel on my K7 Thunder and I was hoping things would be better, and if not then at least I could see something in the logs if it did crash/lock. I also compiled NVidia driver with debugging enabled. Things are no better as the system still locks up frequently while playing Quake 3, and I can't even start Unreal Tournament without it locking and requiring a reset (SysRq, logging in remotely, etc. does not work). The logs tell me nothing.

What I have found is that if I disable DMA on my IBM ATA100 drive, the system is quite stable (though it is slow as snot - running at a ridiculous 4.5MB/sec. as compared to 35MB/sec. with UDMA33/66 enabled). These systems also seem fine when running with Ultra160 drives and no IDE at all (SCSI CDROM, as well as hard drives). Not only is the K7 Thunder system stable, but I can even actually play Unreal Tournament. Other applications that previously locked the systems work fine as well.

Comments?

PGA

Paul G. Allen
UNIX Admin II/Network Security
Akamai Technologies, Inc.
www.akamai.com