Is the UAD-1 PCI-X and G5 compatible?
The UAD-1 does not implement PCI-X, BUT PCI-X slots will operate in standard PCI mode when a standard PCI device is present. Likewise, the bus speed is determined by the slowest device on the bus, so assuming the system's PCI controller is working correctly, the fastest PCI-X/133 slot should behave exactly like a normal PCI/33 slot when a PCI/33 device is inserted.
Looking at the gold finger connections at the bottom of any 32 bit PCI card you will see either one or two vertical slots. The presence of two slots ( as on the UAD-1) means the board is a Universal board and is compatible with both 3.3 Volt and 5 Volt signaling levels. The slot nearest the back panel is the 3.3 Volt slot. The slot furthest from the back panel is the 5 Volt slot. The G5 PCI-X bus will work in PCI mode specifically with 2-slot universal PCI cards so the UAD-1 DOES work in an Apple G5.
http://uaudio.com/support/software/UAD-1/technotesau.html
For more information on G5 PCI-X configurations:
http://developer.apple.com/qa/qa2001/qa1307.html
http://developer.apple.com/docum ... er_5_section_3.html