Originally posted by: homestarmy
My friend wants to drop a crapload of money on a motherboard because it supports 16x16 for two PCI-E video cards at once.
I advised that likely most video cards would not saturate the 8x8 PCI-E bus, so there wouldn't be a bottleneck, and therefore no performance gain going 16x16.
Is this correct?
Originally posted by: homestarmy
Thanks.
So there would be no performance increase at all with that series of card?
What series would start to see a benefit going from 8x8 to 16x16?
Originally posted by: hmorphone
A very small performance gain, and he would probably be much better off selling the 7600 and taking that money and the funds for the second 7600 and getting something like a 7900.
Originally posted by: Crescent13
Originally posted by: homestarmy
Thanks.
So there would be no performance increase at all with that series of card?
What series would start to see a benefit going from 8x8 to 16x16?
Correct.
If you want to help him out even more, tell him not to waste his money on 2 7600 series cards and tell him to spend it on 1 good card. SLI still has alot of limitations, and you'd get more bang for your buck if you get 1 better card (I hear the Voltmodded and Overclocked 7900GT kicks some major @$$ this time of year)
ATI, the Newcomer in the Chipset World
ATI has been a bit late to enter the chipset game and the initial approaches, despite being hyped through the ceiling, never showed any convincing long-term success - courtesy of the little blemishes in the overall facade. In the context of ATI and nVidia, it is impossible to paint the entire picture including the battle between HyperTransport and 3GIO now known as PCIe, the sidings with Intel and AMD, respectively, and last not least the influence of either party on the memory technology developments. However, to make a long story short, ATI's strategy always focused on the 16 lanes PCIe interface supposedly necessary to satisfy the bandwidth demand of concurrent graphics adapter communication with the rest of the system.
This necessity for 8 GB/sec interface bandwidth was also the pivotal point of ATI's campaign against nVidia's SLI solution - since allegedly the two graphics cards in an SLI tandem would starve with only 4 GB/sec data bandwidth available. In a nutshell, whoever came up with this idea, only showed a complete lack of understanding of the idiosyncrasies of system technology, the data traffic bottlenecks are elsewhere but not in the PCIe bandwidth available for each card.
Unfortunately, nothing is as long-lived as utter nonsense, especially when dressed up with pseudo-technology jargon, and for the manufacturers of any given hardware, that means it is easier to play along and ignore facts as long as a product can be offered that complies with the wishful thinking of the PR dream-weavers. In view of the above, it is relatively easy to appreciate where the ATI CrossFire Xpress 3200 chipset comes from, offering dual PCIe x16 slots with 8 GB/sec bandwidth each, that are fairly completely exhausting the HyperTransport link to the CPU (and memory), with no less and no more than 2GB/sec bandwidth in both directions.
Is there? Link?Originally posted by: GundamSonicZeroX
There's a X1950 pro coming for the AGP. And about the 2 7600's, if they're GT then 2 of them will match a 7900 GT.
Originally posted by: Sable
Is there? Link?Originally posted by: GundamSonicZeroX
There's a X1950 pro coming for the AGP. And about the 2 7600's, if they're GT then 2 of them will match a 7900 GT.
Originally posted by: Gstanfor
Two 7600's have no hope of taxing the bus, let alone the fact that the cpu/memory subsystem has no hope of filling the bus with that much data in the first place.
Text
ATI, the Newcomer in the Chipset World
ATI has been a bit late to enter the chipset game and the initial approaches, despite being hyped through the ceiling, never showed any convincing long-term success - courtesy of the little blemishes in the overall facade. In the context of ATI and nVidia, it is impossible to paint the entire picture including the battle between HyperTransport and 3GIO now known as PCIe, the sidings with Intel and AMD, respectively, and last not least the influence of either party on the memory technology developments. However, to make a long story short, ATI's strategy always focused on the 16 lanes PCIe interface supposedly necessary to satisfy the bandwidth demand of concurrent graphics adapter communication with the rest of the system.
This necessity for 8 GB/sec interface bandwidth was also the pivotal point of ATI's campaign against nVidia's SLI solution - since allegedly the two graphics cards in an SLI tandem would starve with only 4 GB/sec data bandwidth available. In a nutshell, whoever came up with this idea, only showed a complete lack of understanding of the idiosyncrasies of system technology, the data traffic bottlenecks are elsewhere but not in the PCIe bandwidth available for each card.
Unfortunately, nothing is as long-lived as utter nonsense, especially when dressed up with pseudo-technology jargon, and for the manufacturers of any given hardware, that means it is easier to play along and ignore facts as long as a product can be offered that complies with the wishful thinking of the PR dream-weavers. In view of the above, it is relatively easy to appreciate where the ATI CrossFire Xpress 3200 chipset comes from, offering dual PCIe x16 slots with 8 GB/sec bandwidth each, that are fairly completely exhausting the HyperTransport link to the CPU (and memory), with no less and no more than 2GB/sec bandwidth in both directions.
A good read, like most lost circuits articles. (No, I'm not picking on ATi here - the same applies equally to nvidia's own nforce4 Pro chipset, it's just that LC chose to have their say on the matter in an ATi review for whatever reason.)
Cheers m'dears. Didn't spot that. :thumbsup:
If you want to do SLI/Crossfire without a bridge/dongle, then the performance is a lot lower (25% or so in many cases) than with one, but that's true with both 8x8 (Crossfire) and 16x16 (SLI).Originally posted by: tanishalfelven
Originally posted by: Gstanfor
Two 7600's have no hope of taxing the bus, let alone the fact that the cpu/memory subsystem has no hope of filling the bus with that much data in the first place.
Text
ATI, the Newcomer in the Chipset World
ATI has been a bit late to enter the chipset game and the initial approaches, despite being hyped through the ceiling, never showed any convincing long-term success - courtesy of the little blemishes in the overall facade. In the context of ATI and nVidia, it is impossible to paint the entire picture including the battle between HyperTransport and 3GIO now known as PCIe, the sidings with Intel and AMD, respectively, and last not least the influence of either party on the memory technology developments. However, to make a long story short, ATI's strategy always focused on the 16 lanes PCIe interface supposedly necessary to satisfy the bandwidth demand of concurrent graphics adapter communication with the rest of the system.
This necessity for 8 GB/sec interface bandwidth was also the pivotal point of ATI's campaign against nVidia's SLI solution - since allegedly the two graphics cards in an SLI tandem would starve with only 4 GB/sec data bandwidth available. In a nutshell, whoever came up with this idea, only showed a complete lack of understanding of the idiosyncrasies of system technology, the data traffic bottlenecks are elsewhere but not in the PCIe bandwidth available for each card.
Unfortunately, nothing is as long-lived as utter nonsense, especially when dressed up with pseudo-technology jargon, and for the manufacturers of any given hardware, that means it is easier to play along and ignore facts as long as a product can be offered that complies with the wishful thinking of the PR dream-weavers. In view of the above, it is relatively easy to appreciate where the ATI CrossFire Xpress 3200 chipset comes from, offering dual PCIe x16 slots with 8 GB/sec bandwidth each, that are fairly completely exhausting the HyperTransport link to the CPU (and memory), with no less and no more than 2GB/sec bandwidth in both directions.
A good read, like most lost circuits articles. (No, I'm not picking on ATi here - the same applies equally to nvidia's own nforce4 Pro chipset, it's just that LC chose to have their say on the matter in an ATi review for whatever reason.)
nice. i never thought about the whole pci-E x16 in that perspective. but don't the cards have to communicate with each other. i suppose the 8GB/sec helps them talk to each other
Originally posted by: GundamSonicZeroX
There's a X1950 pro coming for the AGP. And about the 2 7600's, if they're GT then 2 of them will match a 7900 GT.
Just FYI, the absence of an SLI bridge/Dongle will result in a traffic decrease, not increase.Lonyo, yes, of course, if you don't use the SLi bridge PCI-e traffic will increase, but that applies only to a few mostly lower end cards and certainly not 7900/7600 series cards.
Originally posted by: josh6079
Just FYI, the absence of an SLI bridge/Dongle will result in a traffic decrease, not increase.Lonyo, yes, of course, if you don't use the SLi bridge PCI-e traffic will increase, but that applies only to a few mostly lower end cards and certainly not 7900/7600 series cards.
What is the function of the SLI connector?
The SLI connector is a proprietary link between GPUs that transmits synchronization, display, and pixel data. The SLI connector enables inter-GPU communication of up to 1GB/s, consuming no bandwidth over the PCI Express bus. The SLI connector is not used with some mainstream graphics cards. These graphics cards pass inter-GPU data through the PCI-Express bus, instead of through the SLI connector. For these mainstream GPUs, there is enough excess bandwidth across the PCI Express bus to effectively manage this additional communication. More powerful GPUs require the SLI connector to achieve optimal scaling results.
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