Using an uad1 together with a powercore pci here. Its a bit of an aged DAW (p4 1.8ghz, Gigabyte 8IRXP mobo, 1gig DDR 2100 ram).
I did disable everything in the BIOS that I don't need (com ports, lpt ports, usb2, floppy disk controller, promise raid controller).
Then assigned some IRQs to the pci slots (after I had win2k installed in standardPC mode), so ultimately there are no IRQ conflicts, everything works *really* spiffy even though the machine is rather weak in terms of cpu (also the normal IDE controllers are ata100, not 133 yet, so the installed HDs aren't operating at peak performance even).
Soundcard is rme hdsp w/ digiface. Works fine at 1.5 and 3ms latency, but then the cpu gets eaten by VSTi synths which I use plenty of, so I'm using 6ms whenever I need to load the CPU up to bursting with VSTis and effects.
The DSP cards work nicely in this setup (they have their own IRQ like everything else does).
What should be considered is that theres problems with dual opteron mainboards (MSI and Tyan in particular, the prior has trouble with powercore, the latter with UAD, resulting in huge cpu use even though the plugins are dsp based.. see DAW forum for reference).
Markus