I recall having tried pretty much all of those at one time or another. I had an overclocked IIsi set up for a long time burning audio CDs. Going faster than 2x led to coaster creation. If you've got the time and inclination, I'd love to hear what you discover. And if you have a CDRW disc hanging around, you can keep some coasters out of the landfill...
I've also burned CDs with an SE/30. I no longer remember if I could even burn faster than 1x, but I'm certain that faster than 2x was a no-go.
My PB540c also can't handle burning beyond 2x. Apparently, that's entirely to be expected:
http://www.fortunecity.com/skyscraper/seagate/536/burningcds.html
There's also a nice discussion of SCSI Manager 4.3 (and how it differs from what went before) at
http://www.overnet.de/hhp/mte/manual/scsi_on_mac3.html
That author points out that the IIfx is indeed a special case (because of its support of SCSI DMA), which is why you were able to burn at 6x (*most* impressive!).
I've also burned CDs with an SE/30. I no longer remember if I could even burn faster than 1x, but I'm certain that faster than 2x was a no-go.
My PB540c also can't handle burning beyond 2x. Apparently, that's entirely to be expected:
http://www.fortunecity.com/skyscraper/seagate/536/burningcds.html
There's also a nice discussion of SCSI Manager 4.3 (and how it differs from what went before) at
http://www.overnet.de/hhp/mte/manual/scsi_on_mac3.html
That author points out that the IIfx is indeed a special case (because of its support of SCSI DMA), which is why you were able to burn at 6x (*most* impressive!).