i think it depends on the brand and wether they decided to have backwards compatibility.

i have a 36gb 10k Fujitsu, and with my sca to 50 adaptor it did not work with the older scsi bus,

however i did have a Ultra 160 PCI Card from a powermac G3 server, and that runs the drive good,

i have the card and drive sitting in my powermac 7500, i had to use xpost to boot OSX panther DVD in order to format it.