I used to burn cd's with my Amiga 1200 with a 68030 at 50 MHz. The maximum burning speed I could burn safely was 4 speed, but if you buy a CD-Rewriter with burnproof, you could burn at higher speed. The software I used were AsimCDFS 3.10 and MasterISO 2.4. Version 2.5 has some problems with my Blizzard 1230 SCSI-kit. I haven't try to use makeCD or Burnit. I think 8 MB of RAM is enough to burn a CD. I have in that machine 48 MB of RAM.
