Ultraplex 32x transfer rate

Ultraplex 32x transfer rate

Post by Erik » Sun, 04 Jan 1998 04:00:00

Today I received some results from my CD-ROM benchmark CD Speed.
One of them was from the Ultraplex 32x.
This drive has an average transfer rate of 25x wich is pretty fast
(almost as fast as my HD:)
But aparantely the Ultraplex reaches it's max speed only at 600 MB.
First I thought this was a bit strange, but it actually makes sence.
A CAV drive spins at a constant speed. When the drive reads further
on the disc, there is more data available, so it means that the
transfer rate is higher.
Now, because all CD's have the same format, the speed increase is
constant and the same with all CAV drives.
This would also explain why a Plextor 12/20 reaches it's max speed
earlier then other drives (haven't got any results from that drive yet,
but I've seen people talk about it a few times in this ng).

You can view the results and add yours at:




1. Plextor Ultraplex data transfer rate problem solved.

Plextor, Adaptec, and Erik of CDSpeed might want to consider putting a
note describing this issue on their respective websites.

Adaptec technical support solved a problem I and others have been
experiencing with Ultraplex maximum data transfer rates 8x lower than
they should be and PCAV instead of CAV type reading of data discs for
either 32max or 40max models, as reported by CD Speed under W98 with
Adaptec 2940 series SCSI adapters. CD Speed URLs:


Plextor technical support has been instructing Plextor users of CDR
drives to set their SCSI card configuration such that Initiate Synch
Negotiation is set to NO (default is YES) for both the CDR and CDROM
drives. While setting this parameter to NO might be important for stable
operation of the CDR drive, setting it to NO on the CDROM drive results
in the undesirable performance reduction outlined in the previous
paragraph. Setting the parameter to YES for the CDROM drive resulted in
normal maximum data transfer rate and CAV type reading.


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