Before I start messing around, can anyone refresh my memory on sleep problems with installed PCI to USB adapter cards?

As best I recall, it was mostly about PCI to USB 2.0 adapter cards in G4 towers like Quicksilver or MDD.

Either they'd re-awaken right after getting to sleep, or get caught in a sleep-limbo with computer on, but screen and keyboard off or otherwise unresponsive, necessitating a power-button shut-down.

Was it intrinsic to the system (a PCI card being put to sleep before attached USB devices can acknowledge sleep instructions back through the card?) or a peculiarity of specific card manufacturers, or of a chipset (like NEC or VIA)?

(Card recommendations or warnings are welcome.)

Thanks.