Actually, most A3000's have 3 PC/AT slots...
And they are usable. But, by default, the only connection made to those ISA (PC/AT) slots is power. Some cards, such as a TBC that only requires power, work fine. Other cards, (Network/Modem/Serial/etc) require additional I/O hardware and custom drivers added to the Amiga.
The GoldenGate or Commodore 386 card both have access to enable the ISA slots on big-box Amigas. Finding and configuring the drivers is the biggest challenge. And even once you do, the performance from these cards leaves a lot to be desired.
So, it can be done, but usually it's more of a pain in the butt than it's worth.
