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Running Video Cards in Parallel
G.A. Wells writes "Ars Technica has the scoop on a new, Alienware-developed graphics subsystem called Video Array that will let users run two PCI-Express graphics cards in parallel on special motherboards. The motherboard component was apparently developed in cooperation with Intel. Now if I could only win the lottery."
So what technology did Alienware create here? None..
So they have one of the first MB's with two PCI Express slots. Big deal, soon MB's will contain many PCI-Express slots. Hopefully a lot more than 2.
All you really need is some way to copy the data in memory from one card to another.
Easy solution? Several high-speed serial connections in parallel between the two cards. With a little bit of circuitry on the card dedicated to keeping the data identical.
Or, with a little bit of a performance hit, you could keep each section of RAM separate, and route misses over the cables.
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I belive you need to RTFA, this isnt about dual head setups. one head, two cards
TIAEAE!
Maybe they don't have to cooperate. Graphics card gennerally support the same standard (vga/directx/opengl). Perhaps, the video array will have its own driver/software component to receive the game data then parcel the data to each card.
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I'm sure this will be said a million times during this thread, but this has nothing to do with multiple heads... it has to do with multiple cards serving 1 head.
discrete parallel graphics processing has been around for a while. The most notable example of it is probably 3DFX and their Voodoo-2 cards. However, there's a problem with this tactic, namely, in the "diminishing gains" department.
:)
So here's the question:
-How is pixel processing going to work? For a given frame, there is vertex, texture information, as well as the interesting little shader routines that work their magic on these pixels. How are you going to split up this workload between the 2 GPUs? you can't split a frame up between the GPUs, that would break all texture operations and there would be considerable overhead with the GPUs swapping data over the PCI bus. *MAYBE* having each gpu handle a frame in sequence would do the trick, but, again, it's a dicey issue.
It would appear to me that this dual-card graphics rendering is quite similiar to dual-gpu graphics cards. Except, where in a graphics card you can handle cache/memory coherency and logic arbiting easily due to the proximity of the GPUs, with this discrete solution you run the problem of having to use the PCI Express bus, which, as nice as it is, is certainly not that much faster than AGP.
So I say, power to you Alienware. If you can pull it off with Nvidia, ATi et all, great. It's too bad the cynical side of me thinks this idea reeks of those blue crystals marketing departments love
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Okay, we have a GeForce and a Radeon in parallel. What's the communication protocol that's running over PCI Express that allows them to do that?
Something tells me you need special drivers AND/OR a standardized graphic card accellerator protocol just to pull it off, otherwize you're stuck with two of the same cards.
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Let us not forget that nVidia and ATI both produce chipsets. Multiple graphics card purchases per system would be a dream for them, and they can help in a direct manner. Although there are not many (read as 'maybe a dozen worldwide') boards with dual AGP, the PCI-Express standard will lead to much easier multi-GPU setups. Also, the newest ATI chipsets with embedded GPUs support multi-monitor if an ATI card is used in the empty AGP slot, so you know that these guys already have to have agendas for PEG in mind.
You've been out of the PC market for about a decade then, if you've never heard of PCI-Express. It's been proposed and talked about and raved about for years, but it's just now finally coming to market.
He must have been out of the market for a decade, to have never heard of something which is only just now in the market? What?
I've been half way out of the market for about five years, and I only recently heard of PCI-Express, and I didn't have many details about it. Researching new, not yet marketed technologies isn't the same as "being in the market".