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Date: Wed, 24 Apr 2013 19:59:07 -0400
From: "Tom, KC2ZAT" <kc2zat AT twcny DOT rr DOT com>
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To: geda-user AT delorie DOT com
Subject: Re: [geda-user] Questions before I start building a new home for
 gaf
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Reply-To: geda-user AT delorie DOT com

DJ,
This Email fork has me confused.  I think.  I had no plans to use one of
the AMD APUs.

I understood your reply "ATI Radeon HD 6870" as an indication that you
found this card to work with multiple heads (monitors).  I also
interpreted your response as an indication that your 4 monitors are
driven by 2 cards plugged into the motherboard.  Each card driving 2
monitors.  Please correct me if my understanding is faulty.

Searching with your input in mind, I finally narrowed the field to two
cards.  The Sapphire HD 4870 1G GDD QP and the Sapphire HD 4870 1G GDDR5
PCI-E.

Based on the specs I have at this time, they both appear to be dual head
(dual DVI-D sockets), single GPU, 1 Gb memory, one is PCI-E and I'm not
sure what the other one is.  I'm still working on identifying the other
differences.

I really feel like I'm having a stupid attack with your statement:
> The problems I had were with two identical nVidia cards.  One driver
> binary loaded, but it showed X two driver instances.
I'm reading this as you expected the driver to load once and be "shared"
by all of the monitors/graphics card instances.  That seems like a
reasonable assumption but I'm not understanding how that caused the X issue.

Sorry if I seem really picky on the details.  Before I drop this much of
my hard earned $$$, I want to make sure this is going to work.
Thanks...


Tom, KC2ZAT
"Imagination is more important than knowledge." -- Albert Einstein

On 04/22/2013 03:34 PM, DJ Delorie wrote:
>> Is your comment about the card only, or will this "APU" cause trouble?
> 
> Not sure but I would think so.  Each different GPU chip is a different
> X driver, and if you have more than one X driver you need to use
> Xinerama - unless ATI did something sneaky in their X drivers.
> 
> The problems I had were with two identical nVidia cards.  One driver
> binary loaded, but it showed X two driver instances.
> 
> Before the HD, most four-monitor cards were just two separate cards on
> one PCB, so no different than having two cards.  The HD (and the
> matrox cards) have *one* GPU and thus show one driver instance to X.
>