This article is from the CD-Recordable FAQ, by Andy McFadden (firstname.lastname@example.org) with numerous contributions by others.
CDR-400 (6x4/2MB;SCSI; 'c' is caddy, 't' is tray, 'x' is external)
CRW-4416 (16x4x4/2MB; 'S'=SCSI, 'E'=IDE)
CRW-8824 (24x8x8/4MB; 'S'=SCSI, 'E'=IDE, 'F'=Firewire, 'X'=external)
CRW-2100 (40x16x10/8MB; 'S'=SCSI-int, 'SX'=SCSI-ext, 'E'=IDE, 'IX'=Firewire)
CRW-2200E (40x20x10/8MB; 'SX'=SCSI-ext, 'E'=IDE, 'IX'=FireWire, 'UX'=USB)
CRW-3200 (40x24x10/8MB; 'SX'=SCSI-ext, 'E'=IDE, 'IX'=FireWire, 'UX'=USB)
[ Yamaha departed the optical storage market in February 2003. ]
It has been reported that the CDR-102 is the same mechanism as the CDR-100,
but with the 4x writing feature disabled. There is no known way to convert
it into a 4x writer. Similar speculation has been made about the CDR-200
and CDR-400, and in fact some people have claimed success. Learn all about
R621 at http://www.geocities.com/SiliconValley/Bay/7023/index.html (or
http://home.t-online.de/home/christoph.dittenberger if you prefer German).
It may also be possible to convert a 2260 into a 4260 with the same method,
as well as the 2216 into a 4416.
Yamaha CDR-100 and CDR-102 units have problems doing digital audio
extraction on some discs. See section (4-19).
Yamaha CDR-100s with firmware version 1.08 may experience problems when
recording audio (e.g. a click at the end of tracks recorded with the "copy
prohibit" flag set to "off"). Upgrading to version 1.10 is recommended.
Since the CDR-100 and CDR-102 units don't have flash ROM (and apparently
the upgrade involves more than just changing a ROM chip), the drive needs
to be sent back to the dealer for the upgrade.
The CDR-100 reportedly works best when writing in 4x mode, and may produce
poor results when used to write at 2x or 1x.
The current firmware versions for the older Yamaha drives is v1.12 for the
CDR-100 and v1.01 for the CDR-102. The change was to "allow mastering in
Blue Book specs". If you aren't having problems, don't get the upgrade.
The Yamaha CDR-400 is somewhere around 1.0g.
The CDR-400 is flash upgradeable, and supports packet writing. The tray on
the CDR-400 has been described as "flimsy". The tray eject moves quickly
for the first half and then slows considerably; this is normal.
The CRW-4001/CRW-4260 runs rather hot. External units or extra cooling
fans are recommended.
Some older Yamaha models apparently don't do disc-at-once recording.
However, they will do session-at-once (SAO), which is as useful for
most things and essential for multisession mixed audio and data discs.
With the right software this isn't a problem.
CAVEAT EMPTOR - Yamaha CDR-200/CDR-400. Reports of units breaking down
after a few months have been persistent. It appears that, unless the units
are kept well-cooled, they will start rejecting discs after a month or two
of use. The drives work very well otherwise, and one customer was told
that the CDR-400AT model was a sturdier version.
(It may be possible to fix the drive by tightening some screws and
adjusting some poorly-seated heat sinks on chips.)