[AG-TECH] AG on >10 displays

Christoph Willing willing at vislab.uq.edu.au
Thu Aug 2 21:40:04 CDT 2007

On 03/08/2007, at 2:43 AM, Brian Corrie wrote:

> A couple of comments, questions on this thread...
> Doc, have you tried multiple TripleHead2Go's on a machine with dual  
> output on a single card or with on a machine machine with 2  
> graphics cards? When I was looking at this the Matrox docs that I  
> read stated that one of these combinations does not work. I think  
> it was the dual output on single card hooked up to two  
> TripleHead2Go's.
> Also, related to Chris's previous post. For those that have done  
> this (Chris?) how do you find the performance of these cards  
> pushing this many pixels, especially when pushing live video to the  
> displays? This would be interesting to know if anyone is  
> experimenting with this, as one could imagine many possible  
> bottlenecks...


With DMX, each screen is serviced by its own graphics card (unless  
you now add TripleHead2Go cards too :) i.e. a given graphics card is  
under no particular stress at all. It just receives (via a local  
network) the pixels it is required to display. The main limitation I  
can envisage is the amount of network traffic involved in pushing  
pixels between the "master" and "slave" machines.

For about 2 years, our UQ Vislab AG node was set as a 4x1 graphics  
cluster using DMX i.e. 4 machines, each contributing a sinlge screen.  
They were connected to each other by a 1Gb private network for all  
the pixel traffic. The master machine (acting as AG display machine)  
had a second network connection to the outside world for normal  
network traffic, as did one of the slave machines which doubled as a  
video capture machine. In that scenario we didn't notice any video  
problems. The only reason we've now moved away from that  
configuration is that it didn't support xvideo acceleration which is  
needed for our DV/HDV enabled vic project.


> Nguyen, Doc Lap wrote:
>> Actually, if you use 2 of the Nvidia NVS 440 PCIe x1 quad cards  
>> with 8 TripleHead2Go's, you'd get 8 * 3 = 24 displays on one  
>> computer.  And it works on both Windows and Macs, not sure about  
>> Linux...  I've connected 2 of the TripleHead2Go's on a PC and it  
>> worked fine, so I expect it should work with 8 of them as well...
>>    Doc
>> --------------------------------------------------------------------- 
>> ---
>> *From:* owner-ag-tech at mcs.anl.gov on behalf of Douglas Kosovic
>> *Sent:* Wed 8/1/2007 9:25 PM
>> *To:* ag-tech at mcs.anl.gov
>> *Subject:* Re: [AG-TECH] AG on >10 displays
>> Hi,
>>  > I was wondering if anyone was displaying AG on more than 4  
>> monitors?
>>  > Maybe on something like a Powerwall set up......what video  
>> display cards
>>  > seem to work?  Are you running on several machines?  VGA or DVI?
>>  > I suppose I could run several video display machines to avoid a
>>  > performance hit with service managers on each machine....but I  
>> thought I'd
>>  > check and see if others are successfully doing this already...
>> How about a PC that has 2 PCI-e x 16 slots filled with high-end  
>> PCI-e x 16
>> video cards, each with 2 x dual-link DVI. Then use 4 TripleHead2Go  
>> devices
>> to give a total of 12 displays, see following for info on  
>> TripleHead2Go:
>>   http://www.matrox.com/graphics/en/gxm/products/th2go/
>> I haven't tried it myself, but it would be interesting to see  
>> something like
>> that running.
>> Doug

Christoph Willing                       +61 7 3365 8350
QCIF Access Grid Manager
University of Queensland

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