CrossFire and PhysX
PH!: The Xilinx FPGA based picture composing engine seems to be a very “individual” circuit that could mix any output signals (DVI signals). Would it be possible to combine the signal of independent video cards with a similar FPGA based circuitry?
ED: Yes, it would be possible, as long as the cards are close to working on the same frame (some buffering is available, but it's not infinite).
Hirdetés
PH!: Are there any plans for a motherboard like the Gigabyte GA-8N-SLI Quad that can run four ATI cards working in CrossFire? NVIDIA has quite a few dual GPU products – will we see a similar solution (or a dual-core GPU) from ATI? It would be great to see a dual X1800 XT pushing Adaptive AA for HDTV 1080i :)
ED: Our designs were made to be very scalable. Evans and Sutherland ships a 16 chip version of our chips using super tiling as their default rendering mode. We designed to scale up to 256 chips. So, there's nothing that would prevent it from working technically, but power, heat and cost are the core issues.
source: beyond3d.com
PH!: We haven't tried it ourselves, but word from Canada says that two ordinary X1300 can work in CrossFire, better, with all the features like Super Tile, Scissor and AFR mode. It's clear that the communication in this case is through the PCI Express bus, but what is combining the pictures? Is it the CPU? If two simple X1300 can “CrossFire”, can't any two PCI Express Radeons?
ED: Yes, the communication occurs over PCIe. One of the two cards acts as a virtual “master” card, and displays the image. The slave card can render to the master as peer-to-peer (without system memory) or through system memory. There's no technical reason that we can't run all our X1000's cards in this method. However, if you get to the higher performing cards, they tend to saturate the PCIe bus and so, for them, it makes more sense to switch to the compositing chip, which removes the PCIe bandwidth being used and gives some great new features such as SuperAA. I believe that Cat 5.11 enabled Crossfire on X1300's.
PH!: We hear more and more about Ageia's PhysX PPU, it has even been paired in theory with the Sony PS3. Are physical computations suitable for a GPU? Is it possible that future DirectX (or WGF) will have something like a “DirectPhsyX” extension as a standard library like Direct3D? Is ATI planning to produce a physics accelerator or a driver which makes a GPU (maybe the GPU of a second, PCI Express based ATI video card) doing physics?
ED: One of the things we've been pushing and working on is the general concept of GPGPU. Basically, take non-graphics problems that perform well on parallel computers, and use the GPU to perform those operations. In some of the protein folding and signal processing fields, we see 2x to 7x increases in performance relative to the fastest single core GPUs. We are working with the GPGPU field to develop further these types of applications. However, it's still too early to say how things will develop. But under the banner of GPGPU, we can include physics computations that lend themselves to parallelism. In general, those are the types of physics computations done in a co-processor, and that justify the co-processor. I believe a lot of that could be done in a GPU as well. As for API extensions, you'd need to talk to MS J
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