My LiteOn LTR48246S is limited to 32x when reading (S)VCDs, even when scanning e.g. with CD-Speed quality check. MInfo shows this read speed too. According to Inertia, it is a common practice to limit the read speed, but I haven't seen any information for other drives.
Just out of curiousity- what is the maximum speed for reading (S)VCD's on your drive?
G