From: jching@watnow.uwaterloo.ca (John Y. Ching)
Subject: SUMMARY: Adaptec 1542B SCSI Controller and ATI Ultra+ Conflict
Organization: University of Waterloo
Date: Tue, 5 Jan 1993 23:34:11 GMT

Hi there,

Just before the holidays, I posted a message asking for help regarding
conflicts between the AHA1542B SCSI controller and my new ATI Ultra+
graphics card.  I received a number of helpful emails from some of you
as well as a few inquiries from those who are planning to purchase the
1542B and/or Ultra series cards.  I am happy to report that my problems
seem to be resolved and here's the summary of what I went through.

Recall that my system is a 486/33 with AMI bios and 8 MB ram.  I have an
AHA1542B SCSI controller mated to a Fujitsu 520mb drive.  I used to have
an ATI Wonder XL VGA card with no problems.  As soon as I upgraded my
XL to an ATI Ultra+, my Windows 3.1 started to crash frequently whenever
I used the ATI Mach32 drivers that came with the card.  I also tried the
8514/A drivers that came with Windows, and that seemed to work fine except
it was much slower than ATI's more optimized drivers.  Suspecting a conflict
between the Ultra+ and one of my other cards, I pulled out everthing except
the 1542B and the problem remained.  Finally, I replaced the SCSI combo
in my system with an IDE card and drive from my other computer, and the
problem went away.

So I concluded that the problem must be due to the combination of the 1542B
and the Ultra+.  Based on suggestions from the net, I tried installing
the two cards in distant slots (one person had a conflict whenever the
two cards were physically close together!) with no luck.  I also tried 
different interupt, base address and DMA combinations and the problem
remained.  Some of you suggested that I try to exclude the memory address
used by Ultra+'s ROM in my SYSTEM.INI, and that didn't help either.  I
tried different memory managers (QEMM and HIMEM.SYS/EMM386.EXE) and still my Windows kept crashing on take off.

Finally, I was so upset I took the Ultra+ back to the dealer and demanded
a refund.  The dealer convinced me to try a different card eventhough I
knew the original card worked fine in my other machine and without the 1542B
controller.  As I expected, the new card behaved identically with the
original one and I took the second card back to the dealer.  This time, the
dealer suggested that refund is impossible but I was welcome to exchange it
with anything else in the store.  I noticed that the store had a new shipment 
of Ultra+ and Ultra Pro cards packaged differently from the two I tried.  
Further inquiry revealed that the two I tried were OEM versions of the Ultra+
and the "new" packaging is the "real" ATI line.  I was then assured that
the OEM versions are identical to the "real" ATI cards and in fact they were
sold at the same price.  Out of curiousity, I asked if I could try one of the
"real" ATI Ultra+ cards.  The dealer agreeed since no cash refund was 
involved and I installed the third Ultra+ (a real ATI this time) in my 486.

Guess what?  All of my problems suddenly disappeared!  My Windows runs 
smoothly with the same old settings using the same Mach32 drivers that
used to crash on me with the OEM cards.  I am not sure why this happened.
Is the OEM card somehow different (other than the built-in mouse port) than
the real ATI's?  Or perhaps the two cards I tried earlier were both defective?
Anyway, my system now appears to work beautifully, and the improvement in
speed in 1024X768 Windows is truly amazing!


-- 
 John Y. Ching (jching@watnow.waterloo.edu)     
 Pattern Analysis and Machine Intelligence Group
 Department of Systems Design Engineering      
 University of Waterloo, Canada            
Newsgroups: comp.periphs.scsi,comp.sys.ibm.pc.hardware