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New Multi-GPU Technology With No Strings Attached
Vigile writes "Multi-GPU technology from both NVIDIA and ATI has long been dependent on many factors including specific motherboard chipsets and forcing gamers to buy similar GPUs within a single generation. A new company called Lucid Logix is showing off a product that could potentially allow vastly different GPUs to work in tandem while still promising near-linear scaling on up to four chips. The HYDRA Engine is dedicated silicon that dissects DirectX and OpenGL calls and modifies them directly to be distributed among the available graphics processors. That means the aging GeForce 6800 GT card in your closet might be useful once again and the future of one motherboard supporting both AMD and NVIDIA multi-GPU configurations could be very near."
I gave TFA a quick perusal and it looks like some sort of profiling is done. I was about to ask about how it handled load balancing when using GPU's of disparate power, but perhaps that has something to do with it. It may even run some type of micro-benchmarks to determine which card has more power and then distribute the load accordingly.
I'll reserve judgement until I see reviews of it really working. From TFA it looks like it has some interesting potential capabilities, especially for multi-monitor use.
ATI were bought out by AMD, so future ATI GPUs will be released by AMD.
The revolution will not be televised... but it will have a page on Wikipedia
Power supply units only supply so much energy, and before then cause interesting system instability.
Also, given the increasingly growing cost of energy, it might be worth buying a newer generation card just for the sake of saving the energy that would be used by multiple older generations of graphics cards. Not the newer cards use less energy in general - but multiple older cards being used to approximate a newer card would use more energy.
I guess power supplies are still the underlying limit.
As an additional aside, I'm still kind of surprised that there hasn't been any lego-style system component designs. Need more power supply? Add another lego that has a power input. Need another graphics card? Add another GPU lego. I imagine the same challenges that went into making this hydra GPU thing would be faced in making a generalist system layout like that.
Ryan Fenton
I agree this is a common problem in modern games; see http://www.gamasutra.com/view/feature/1942/programming_responsiveness.php
Don't confuse control latency with reaction time. Reaction time will be at least 150ms for even the best players, but humans can notice time delays much smaller than best reaction time. A good rhythm game player can hit frame exact timing at 60fps -- a 17ms time window. With low enough latency the game character feels like a part of your own body, rather than something you are indirectly influencing.
The same thing applies to GUIs, and only a very short delay will destroy that feeling of transparency of action. I never actually used BeOS myself, but I read that it was designed with low interface latency as a priority, which was why it got such good reviews for user experience.
Latency will be a problem. All that extra message passing and emulation layers.
Already, most Windows 3d games lead me feeling a little disconnected compared to DOS games.
The sound effects and graphics always lag behind the input a little.
Try playing doom in DOS with a soundblaster, then try a modern windows game. With doom you hear and see the gun go off when you hit the fire button. In a modern 3d game, you don't.
I've experienced the same thing over a number of different computers.
Most monitors have about a 30-50 ms input lag, meaning the image is always a frame or two behind in most modern games. You can get a 0-5 ms input lag monitor, though. The DS-263n is a good example. I felt like everything was lagged ever since I switched to LCDs, but once I picked up the 263, that feeling is gone. The feeling of sound lagging input could be a different issue or it could be psychological.
"I zero-index my hamsters" - Willtor (147206)
> How did anyone get "vastly different GPUs" from this?
Presumably because (for e.g.) a G70-based 7800 and a G92-based 8800GT are vastly different GPUs.
G70, for example, had two sets of fixed-purpose pipeline units (one of which ran your vertex programs, and one of which ran your fragment programs,) a bunch of fixed-function logic, some rasterisation logic, etc.
On the other hand, G80 and above have general purpose 'shader processors' any of which can run any pipeline programs (and, afaik, runs the traditional graphics fixed-function pipeline in software on said SPs), and a minimal amount of glue to hang it together.
About the only thing that current-generation GPUs and previous-generation GPUs have in common is the logo on the box (this applies equally to AMD parts, although the X19xx AMD cards, i'm told, are more similar to a G80-style architecture than a G70-style architecture, which is how the F@H folks managed to get it running on the X19xx before G80 was released.)
You're doing it wrong.
From the screen shots and the description, it sounds like this thing takes the d3d (or ogl) instruction stream, finds tasks that can be done in parallel and partition them up across several cards. Then it sends each stream to a card, using the regular d3d/ogl driver for the card. At the back end it merges the resulting framebuffers.
What I'd like to know is how they intend to handle a situation where the gpus have different capabilities. If you have a dx9 and a dx10 card, will it fall back to the lowest common denominator?
Also, what about cards that produce different results? Say, two cards that does anti-aliasing slightly different. The article says that Hydra will often change the work passed off to each card (or even the strategy for dividing work amongst the cards) on a frame by frame basis. If they produce different results you'd end up with flicker and strange artefacts.
Sounds like interesting technology but unless they get all those edge cases right...
If J.K.R wrote Windows: Puteulanus fenestra mortalis!
Presumably he's North American, we (among a few other places) use 120v lines, 240 is reserved for special high power circuits, generally only used for dryers, stoves and refrigerators (and only some of the first two).
Yes, CRTs have something like 1-2 ms latency + refresh rate.
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