Q: What kind of USB PCI Card should I get for a 1997 PowerMac G3?

What company manufactured the USB controller chip on the card (not the brand of the card)?  You might have to peel off a sticker to read the name.  Is it VIA or Opti?  Those cards were problematic for the beige G3s and could cause freezing.  I had success with a 2-port IOGEAR USB 2.0 card in my fleet of beige G3s, which I attribute to them having an NEC controller chip.

My Beige G3 has a Macally UH2-222 that never gave any issues. It has the preferred NEC chipset. They are discontinued but you will still find them around on the used market, sometimes still in the box. You must use their software to get the thing to work in OS9. If you dont get an original disk with the card, here is the link to their archived drivers page:

http://macally.com/EN/techsupport/drivers/drivers.html

You need to scroll about halfway down to this link (screenshot):

Allan:  The link on the Macally page was to an Apple software download ("USB Adapter Card Support 1.4.1"), but it's dead now.  In any event, the newer USB Support drivers that came with OS 9.1, 9.2.1, and 9.2.2 are far better, in that they have an updated database of supported devices.  The O. P. has indicated that his G3 is running OS 9.2.x., so if he uses TomeViewer to extract the USB drivers from the OS 9.2.1 or 9.2.2 Update, he'll have better luck with device recognition.  If he posts back, I'll list the files that he needs to extract from the System Update Tome.

Thanks Jeff. I had installed the USB driver from the Macally CD originally but now realize that subsequent updates of OS9 upped the versions. The Beiges are currently covered up right now to protect them from construction activity late last year. Time to fire them up again!

I used (still have probably) an Orange Micro USB/Firewire card in my G3 successfully. It too requires its special drivers and they didn't bring out any version for OSX. I remember not being able to transfer it to my G4 for use under Tiger OS.

If you live in a large city there may be a Mac User Group where people have old stuff they might be happy to donate.

Perhaps a 5-port USB 2.0 card is too much for the first generation (1997) of beige G3s, because it draws too much power.  Maybe it has to do with the fact that each port on a USB 2.0 card is on a separate bus with its own controller.  I have a couple of early-1998 beige G3s with the first revision motherboard.  I replaced the original ROM card with the improved Rev. B card to support configuration of dual hard drives and/or optical drives (master - slave) on both IDE buses.  This is something that a G3 manufactured in 1997 won't support, if the original revision ROM card is still installed on the motherboard.  I used the IOGEAR GIC220U 2-port USB 2.0 PCI card in all of my beige G3s and a pair of Blue & White G3s.  It's no longer manufactured, but there are some listed on ebay, used and new-in-box.  I never had any problem with it in the beige G3s, as it was primarily installed for use with flash memory drives.  In my B&W G3s, the card provides the faster USB 2.0 speed that's supported by OS X (Jaguar, Panther, and Tiger).  When booted from the OS 9.2.2 partition, the card functions at the slower USB 1.1 speed.

I'm too lazy to go down to the basement and have a look but I think my Orange Micro has one of those internal ports too.  I don't know what they are for but if you had a spare flash drive you could bump up the storage on the computer significantly, particularly if you ran OSX so it would run at USB2.