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It depends on the USB specifications of the card. Newer PCI cards support a newer PCI standard (sorry, I don't know the version numbers) that enable them to work fine in PCI-X slots.

With this sort of thing I always check http://www.xlr8yourmac.com There's always a wealth of information on there with all the gory details.

Worth noting that I bought a Belkin 4 port USB 2 card and that installed fine. Some problems with it though - Any devices plugged into it on startup have to be unplugged and plugged back in before they work. With some devices connected when you put the computer to sleep it wont wake up again, or after several minutes the mac goes into 'Take off' mode where fans blow at full pelt, requires a hard reset.
 
Pretty much any main brand and type of PCI card has probably been tried in a PMac G5, with the results posted on xlr8yourmac (god I sound like I'm trying to advertise that place) Always have a dig about on there first before purchasing.

What sort of PCI card are you looking for?
 
TMA said:
Pretty much any main brand and type of PCI card has probably been tried in a PMac G5, with the results posted on xlr8yourmac (god I sound like I'm trying to advertise that place) Always have a dig about on there first before purchasing.

What sort of PCI card are you looking for?

Just want to put a USB 2.0 card and a FW 400 card in a PM G5 I'll be buying in the next week - trying to have all my ducks in a row. ;)
 
Be careful. I got an adaptec firewire 400/USB 2.0 card that doesn't work in my G5. There are tons of sleep issues with these USB cards.
 
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