[PD] Best PD-GEM Performance Computer ... + wiki

B. Bogart ben at ekran.org
Mon Feb 28 17:18:23 CET 2005

Hey Winfried,

I've been using pd/Gem on Macs and on Linux machines. For lots of video stuff I 
would certainly suggest going with a Mac, dispite the extra cost. This is due to 
the very optimized commercial video decoders in quicktime. For a Mac I would get 
the best ATI card available, Radeon 9800PRO? For linux I would certainly suggest 
an Nvidia card, though the drivers are not free, they are 100% fully functional 
(for example video output on a radeon card on linux is often not possible). I've 
not looked into what Nvidia gfx cards are the best here.

As for professional vs comsumer graphics cards I would guess to say that the 
Quadro line is probably not going to help you much. I've been told that the only 
real difference between these cards is the amount of acceptable error in the 
output. For less error you pay twice as much. The gamer market has only really 
been pushing the consumer cards (obviously) and so I would argue these give the 
best value for the money.

I don't see how you can run four screens off one computer, are there 4HEAD fast 
openGL cards out there??? I would say you need two machines with dual-head 
cards. Note that two machines with dual heads is going to be way faster than one 
machine with 4.

A friend did an installation using pd/Gem on 3 machines, each controlling one 
projector. There was no noticable lack of sync between the machines, controlled 
via netreceive on local LAN. I don't think there is any issue with the video 
card rendering being in sync between the two machines, nor anyway of doing this 
I can think of? (some odd use of [t a a] and only rendering frames on one 
machine when it gets the gemchain signal from the other machine?)

Alright James and Chris, what do you pros think?

Oh and for multi-screen display check out this:


LightTwist is a GPL system for correcting distortion caused by projecting on 
irregular surfaces, as well as matching multiple projectors into one seamless 

Eventually (next year?) pixelTANGO (a high-level set of abstractions for pd/Gem) 
will be the preffered way to generate images for the lightTwist system.

Thats my opinion.


Winfried Ritsch wrote:
> Hi,
> We have to assemble one special PD/GEM Performance Computer and also I always 
> got some questions about Computer best for PD performance. 
> I Started a Wiki which discuss dedicated PD Computers (also embedded ones). If 
> someone has made some special hardware and/or experiences, it would be nice 
> it will be shown there... http://puredata.info/community/projects/pdcomputer/
> My questions now: 
> a) Quadro vs. geforce:  If I want display on multiple large screens, (is 
> there) what is the benefits of NVIDIA quadro cards to geforce (eg. 6800 SLI) 
> on signal quality rendering benefits. ?
> Which feature are most important projecting on big screens ?
> b) If I do 4 projections on a big screen so they are merged to one picture, 
> must the video be displayed in frame sync (maybe using more than one 
> computer) from the beamer/videocard view (not the video frames as 
> content).  ?
> mfg winfried
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