This article is from the storage FAQ part1, by Rodney D. Van Meter with numerous contributions by others.
Seagate's Elite 9 is 9GB -- reports here of backordering, others of availability. Micropolis due out with an 8GB soon? (94/9/1) The fastest (in sustained transfer rate) known 5.25" disk drive is the ST12450W2HP 1.78GB Barracuda drive from Seagate. The Barracuda family is large, so pay attention to the model number! It runs at 68-113 Mbits/sec., depending on head position (it's ZCAV). Assuming that data rate is pre-format, and subtracting 20% for the format overhead, that would be a sustained rate of 6.8-11 MB/sec. Of course, your mileage WILL vary according to transfer size, locality, etc. (rdv,95/2/7) Seagate announced a couple of weeks ago a 23GB disk drive. Reportedly shipping in summer. (Brian A Berg <firstname.lastname@example.org>, 1996/3/29)