I just read a review on the 5970 where it stated this chip simply matched the performance of the old sideport.
[BW] PLX PCI Express Switch Enables Blinding Speed on New ATI Radeon Flagship
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| PLX PCI Express Switch Enables Blinding Speed on New ATI Radeon Flagship Graphics Card SUNNYVALE, Calif.--(BUSINESS WIRE)--PLX Technology, Inc. (NASDAQ
“The ATI Radeon HD 5970 graphics card, supported by the PLX® PEX 8647, exemplifies top performance for today’s extreme computer games,†said Rick Bergman, senior vice president and general manager, AMD. “AMD chose the PLX chip for its industry-leading features, allowing very high-speed communication between our two powerful, next-generation Radeon graphics processors. The PEX 8647 switch has provided enhanced flexibility and performance in our HD 5970 design and enables AMD, and its partners, to provide customers the fastest graphics solutions on the planet.†“High-end graphics controllers and cards need high-end IO so their data can move from chip to chip, card, system, and screen,†said Shane Rau, PC semiconductor research director at IDC. “PCI Express 2.0 is now the leading-edge IO standard for all high-end graphics cards in the PC market and compatibility with it is essential for market leadership.†The PLX ExpressLane™ PEX 8647 switch is specifically designed for the cutting-edge graphics industry. The PEX 8647 is a 48-lane, three-port, PCI Express Gen 2 (5.0 GT/s)-compliant switch featuring... |
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That article was a lot of vague boasting - like a press release more than an article. It didn't really explain what the chip does (read: how it works) or why it is better than the old way of doing things, which is what an article or review would/should do.
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I do not think the sideport features are enabled, either. Also, by "software" do you mean "drivers?"
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Originally Posted by darksideleader last time i checked, they didn't even enable sideport with the 4870x2? Apparently it raises the power comsumption and heat with very minimal gains, probably cuz the 4870 doesn't need that much bandwith. ATI has the best tech, but the software is missing. Unleash those 3200 shaders ATI... |
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It is a press release.
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Originally Posted by stargate125645 That article was a lot of vague boasting - like a press release more than an article. |
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I believe you are talking about memory bandwidth, not the bandwidth that the cores are using to talk to one another, which at least used to be the PCI-E interface bus.
Originally Posted by Bleached Most likely the 128bit bus is strangling the bandwidth between the GPU's. Sideport is enabling them to talk to each other faster. Makes sense to me. Everyone thought that 128bit bus was too small anyway. |
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You are right. My mistake.
Originally Posted by stargate125645 I believe you are talking about memory bandwidth, not the bandwidth that the cores are using to talk to one another, which at least used to be the PCI-E interface bus. |
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You may think that, but I'm waiting for Duckie to come in and tell me what I missed.
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Originally Posted by Bleached You are right. My mistake. |
Yup..... press release.... bandwidth isn't really an issue since "9x PCIe 2.0 worth of bandwich" is good enough for current cards.
Now, what's the latency numbers?
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Now, what's the latency numbers?
I don’t know… I wouldn’t call it fluff. Since the 5870 has been shown to have a slight decrease in performance when ran at pci-e 2.0 8X, there was some cause for concern that the 5970 would exceed the bandwidth of pci-e 2.0 16X. Perhaps there goal with the Gen 2 PCI-e switch, was merely to maintain the performance of (2) 5870 CF, instead of increase. Just a thought.
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Never happened because as i posted earlier sideport turned out to be unneeded.
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Well duh, it has lower clocks to keep within the 300W TDP limit of PCIE 1.x . Put it in a PCI-E 2.x slot and crank the cores.
Originally Posted by Robilar As noted above, looks like another Sideport fiasco. I had several 4870X2's and waited patiently for ATI to enable its "10-20%" performance boost via sideport ala driver updates. Never happened. |
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Originally Posted by Interview with Dave Baumann A reader question: I had a user question asking, what happened to Sideport (XSP)? Sideport was intended to add more interconnect bandwidth. It has been disabled ever since the release of the RV770 (X2) from day 1. We heard that "that much bandwidth is not needed". IMO... you can never have enough bandwidth really. What was going on there? This is simply a case of our software capabilities catching up to our hardware capabilities. When the initial design of the RV770 was taking place and concepts such as Sideport were being kicked around our ATI CrossFireX™ software wasn't in the place it is right now, so there was a much higher reliance on inter-chip communication. While having lots of bandwidth is rarely a bad thing, the ATI CrossFireX communication bandwidth between two discrete cards is less than local bandwidth - even though Sideport doubles the inter-GPU communication bandwidth on an X2 type solution it's still not significant enough to really change the disparity in local frame buffer and inter-GPU bandwidths. The software work that occurred in the space of time between the RV770 design and product saw significant improvements in inter-GPU communication. Internal to the driver we now have a number of "alternate frame rendering" (AFR) profiles, with many parameters that can be tweaked in order to control how the rendering behaves over multiple GPU's and reduce the inter-GPU communication as much as possible. By the time we put two RV770's on a board and started testing Sideport, the current ATI CrossFireX software capabilities delivered more than enough bandwidth, obviating the need for Sideport. |
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Originally Posted by 003 That is all fine and nice but a 5970 is still slower than 5870 CF... |
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Of course it is, it's equivalent to a 5850 CF pretty much...
Just like a GTX 295 isn't a GTX285 in SLI, but an underclocked GTX275 in SLI.
Originally Posted by 003 That is all fine and nice but a 5970 is still slower than 5870 CF... |
Just like a GTX 295 isn't a GTX285 in SLI, but an underclocked GTX275 in SLI.
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Are you correcting someone, or is this a Captain Obvious moment?
Originally Posted by 003 That is all fine and nice but a 5970 is still slower than 5870 CF... |
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Well the article makes it seem like this PLX chip is equivalent to the second coming, and yet the card performs worse than 5870 CF and when clocks are increased to those of a stock 5870, the performance is virtually identical to 5870 CF. So I don't understand why such a big deal is being made over the PLX chip.
Originally Posted by grunion Are you correcting someone, or is this a Captain Obvious moment? |
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Because it's a press release.
Originally Posted by 003 Well the article makes it seem like this PLX chip is equivalent to the second coming, and yet the card performs worse than 5870 CF and when clocks are increased to those of a stock 5870, the performance is virtually identical to 5870 CF. So I don't understand why such a big deal is being made over the PLX chip. |
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Really? All I see is "It is used on the fastest graphics card on the market"
Is that false?
Originally Posted by 003 Well the article makes it seem like this PLX chip is equivalent to the second coming, and yet the card performs worse than 5870 CF and when clocks are increased to those of a stock 5870, the performance is virtually identical to 5870 CF. So I don't understand why such a big deal is being made over the PLX chip. |
Is that false?
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