It depends on the card. Some (most?) cards will let your PCMCIA work just fine.
This hits it. I used an A1200 for years with a DKB '030 card, with at least 32Mb of RAM (up to 128Mb), and a Squirrel SCSI or LAn card in the PCMCIA slot. I used 3.1 ROMs with 3.1 or 3.5OS. Everything worked fine.
It all depends on the card, AND where the RAM is mapped. AFAIR the 4Mb problem was only with early cards....
