heres some notes on what vintage macs have "Simple serial ports" great for MIDI
to avoid + sidestep the issues discussed in the above article:
similarly i think these nubus machines are the only machines that can properly run SOUND DESIGNER app with the digidesign audiomedia II nubus card or pro tools nubus cards that it requires


Nubus Capable
Macintosh II 16 MHz 68020 x6 nubus slots ********** perfect!
Macintosh IIx 16 Mhz 68030 x6 nubus slots ********** perfect!
Macintosh IIfx 40 MHz 68030 (expensive) 6x nubus slots
Macintosh IIcx 16 MHz 68030 3x nubus slots ********** perfect!
Macintosh IIvi 16 MHz 68030 3x nubus slots ********** perfect!
Macintosh IIci 25 MHz 68030 3x nubus slots ********** perfect!
Macintosh IIvx 32 MHz 68030 3x nubus slots ********** perfect!
Macintosh Performa 600 (CD) 32 MHz 68030 3x nubus slots ********** perfect!
Macintosh Quadra 700 25 MHz 68040 (expensive) 2x nubus slots
Macintosh Quadra 900 25 MHz 68040 (expensive) 5x nubus slots
Macintosh Quadra 950 33 MHz 68040 (expensive) 5x nubus slots
No Nubus slots:
Macintosh Classic 8 MHz 68000 (weak cpu)
Macintosh LC 16 MHz 68020 (weak cpu)
Macintosh LC II 16 MHz 68030 ********** perfect! but no nubus slots
Macintosh Performa 200 16 MHz 68030 (rare?)
Macintosh Performa 400 16 MHz 68030 (rare?)
Macintosh Classic II 16 MHz 68030 (no nubus slots)
Macintosh SE/30 16 MHz 68030 (hard to find)
Macintosh IIsi 20 MHz 68030 (no nubus slots)
Macintosh Quadra 630 33 MHz 68040 ********** perfect! but no nubus slots
http://www.everymac.com/systems/apple/mac_quadra/specs/mac_quadra_630.html[/size]
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http://www.everymac.com/systems/apple/mac_classic/specs/mac_colorclassic_ii.html Processor Speed: 33 MHz Processor Type: 68030
(power of a IIvx with no nubus slots)
https://68kmla.org/forums/index.php?/topic/30897-quadra-630-owners-question-re-serial-port-performance