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Old 07-20-06, 09:35 PM   #1
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Join Date: Jul 2006
Posts: 4
Question Xinerama and GLX with dual GPUs, compatibility question


First of all, I'm new here, I hope this is the right place to ask this.

I'm currently speccing out a new Linux-based workstation and would like to upgrade from my current dual-head setup to three monitors. I know this works fairly easily with Xinerama, but I'd also like to have OpenGL acceleration as I do a lot of (OpenGL) graphics programming and switching back to dual head for that would be rather inconvenient.

I've read the relevant topic in the nVidia driver readme, but before dropping a significant amount of money on the planned setup, I'd like to make sure it's actually going to work.

What I'm thinking of here is two cards, one with 2 DVI displays attached, the other with 1 DVI display. As far as I can tell, the card with the 2 displays needs to have TwinView enabled. Note that I'm not talking about SLI, I know that that only supports one display.

- First of all, I can't afford two GeForce 7900s, so I'd ideally want to use two different cards for this setup, the document linked above hints that this is possible. Given current consumer-level cards, what combinations are known to work? Specifically, I was looking at the GeForce 7900GT, 7600GS, and 7300GT. Will any combinations of those cards work in such a setup? Ideal case is of course 7900GT with 7300GT in terms of speed-price tradeoff - if it'll work.

- Assuming I get two different but compatible graphics cards, and I have an OpenGL window that doesn't cross monitor boundaries, will the speed of the rendering be affected by the other card? So if I have the OpenGL window on one of the faster card's screens, will it run at maximum speed for that card, or will the slower card slow it down in any way? (compared to two identical cards, say)

- Will there be problems with TwinView and GLX/Xinerama interacting? If so, what problems, and will using 3 separate cards (7900/7600, 7300, 7300?) solve that? (I've not got any components for the new system yet, so getting a motherboard with 3 PCIe graphics slots is possible, though I'd like to avoid it as they're rather expensive)

Any help or comments are appreciated.


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