Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!asuvax!mcdphx!teroach.UUCP!stan
From: stan@teroach.UUCP (Stan Fisher)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: A2091 & CDC Wren III
Message-ID: <12540@mcdphx.phx.mcd.mot.com>
Date: 26 Feb 90 21:56:46 GMT
References: <05034.AA05034@alison>
Sender: listen@mcdphx.phx.mcd.mot.com
Reply-To: stan@teroach.UUCP (Stan Fisher)
Organization: Motorola Microcomputer Division, Tempe, Az.
Lines: 29

In article <05034.AA05034@alison> mjl@alison.UUCP (Martin J. Laubach) writes:
>
>  I don't think the 2091 (or 590) is faster than the 2090 -- my
>experiences have been that the 2090 outperforms a 2091, especially on
>small data transfers (the 2090 has an additional Z-80 doing all the DMA
>and SCSI setups, while on the 2091 all that stuff is directly handled by
>the main processor). On large transfers (>64K), the 2090 still is a bit
>faster than the 2091 (something like 650 vs. 500 K/s).
>
> mjl    //	Usenet: mjl@alison.at or ..uunet!mcsun!tuvie!alison!mjl
>      \X/	Fido:   2:310/3.14


I beg to differ.  It's pretty hard to make a blanket statement about which
controller is faster _period_. 
Example:
You've seen situations that make you believe the 2090 is faster than the
2091.  I dropped a 2091 into a 2500/20 in place of a 2090A and compared
diskperfs with virgin fresh formats on a Micropolis 158 meg SCSI drive and
saw speed improvments of around 20% overall.  This was the exact same
hardware except for the 2091/2090A swap, both to the same drive with a
fresh format.  I really can't say which controller handles a well
used/fragmented partition with lot of data on it.
So to me.. The 2091 is decently faster.  Around 950K (max) diskperfs on my
setup.

  Stan Fisher -  stan@teroach.phx.mcd.mot.com -  asuvax!mcdphx!teroach!stan
  Motorola Microcomputer Division, Tempe, Arizona   -  Voice (602) 438-3228
  Call our User Group BBS "M.E.C.C.A." running Atredes 1.1 @ (602) 893-0804