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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Damion on February 13, 2010, 09:54:53 PM

Title: A3000 SCSI transfer rate
Post by: Damion on February 13, 2010, 09:54:53 PM

Hi,

Been playing with my A3000D the last few days, and am curious what kind of performance is possible with the onboard SCSI.

With a CSMK-II '060 and all the latest chips, I'm getting about 3.7 MB/s synchronous. I know the WD33C93 is ancient, but I was hoping for a little better since I'm considering temporarily retiring the A2000, but sadly the MK-II SCSI doesn't fit in the A3000D, and my A2K/TekMagic has an excellent SCSI controller (10 MB/s). So it's a toss-up - Z3 vs better SCSI. :P

It would seem according to this (http://www.mail-archive.com/linux-scsi@vger.kernel.org/msg05555.html) page that faster rates are in theory possible, and I've heard rumors of 6 MB/s on the A3000... if all else fails, I suppose another faster option would be some type of flash drive with a DENEB.

*edit* Also, I keep reading about a "J800 WD33C93 Speed" but I must be blind, cuz I don't see a J800 on either of my A3000 motherboards...  :-o

Title: Re: A3000 SCSI transfer rate
Post by: Amigaz on February 13, 2010, 10:45:57 PM

I'm afraid you wom't get any higher speeds than roughly 4mb/s (synch) with a 10-15k SCSI drive..even with the latest WD chip
I experimented alot trying to reach higher speeds than 4mb/s on my A3000 whih also had a CS MKII (now sold) latest WD chip...the SCI circuitry is just too old and acts as a bottleneck
We have to remember that 4mb/s was fast back in 1990 when the A3000 came out

Title: Re: A3000 SCSI transfer rate
Post by: matthey on February 13, 2010, 10:53:59 PM

I remember getting roughly 4 MB/s with syncronous enabled in the 3000 volatile memory and all the latest chips. You need SCSIPrefs (Aminet) or similar to enable. 5 MB/s is the theoretical limit of 50 pin SCSI 1/2. Unless someone figured out how to hack in fast SCSI 2 which IS supported by the upgraded SCSI chip, then the 6 MB/s is BS. Maybe they were talking about a 4000T which does support fast SCSI 2.

Title: Re: A3000 SCSI transfer rate
Post by: Damion on February 13, 2010, 11:08:18 PM

Cool, it's as fast as it's gonna get then (a bit under 4 MB/s measured with RSCP). It's not unbearable, just a little sluggish which is to be expected.

Title: Re: A3000 SCSI transfer rate
Post by: jsixis on February 13, 2010, 11:24:34 PM

Using diskspeed I have never gotten over 2.1 mb.

Title: Re: A3000 SCSI transfer rate
Post by: Tension on February 14, 2010, 12:13:00 AM

What's the MB/sec for an A4000D/040 IDE HD using the standard port?