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Vraagje voor de kenners over PCI-E 2.0 16x ivm met een mogelijke CF opstelling met 1 'PCI-E 16x 2.0/16 lanes' en 1 'PCI-E 16x 2.0/4 lanes'.
Voor mijn 955BE en 5850 systeem zit ik nu te denken aan de Asus M4A785TD-V EVO.
Dit mobo heeft voor de 2 maal PCI-E 2.0 16x, 16 lanes voor de 1e en 4 lanes voor het 2e GPU slot.
Dit wordt als onvoldoende voor CF gezien, toch? Dat is tenminste wat ik tot nu toe heb begrepen.
Nu las ik net op TechPowerUp een review over de 5870 kaart waarbij deze opeenvolgend werd aangesloten op: Een PCI-E 2.0 8x, een PCI-Express 2.0 4x en zelfs een PCI-Express 2.0 x1
quote uit de review;
"It holds even more relevance to users and potential-users of most socket LGA-1156 motherboards, as this is where 16 lanes from the processor's on-die PCI-E switch are split into two 8 lane links. Surprising as it seems, the Radeon HD 5870 is comfortable, with a mere 2% performance drop overall. PCI-Express 2.0 x4 is where the Radeon HD 5870's discomfort is slightly notable, with a 5% drop, and even more surprisingly, on PCI-Express 2.0 x1, big as it seems, the performance drop is "only" 25% overall. Considering that you rob the card most of its data transfer potential, leaving only a 1/16th of the optimum bandwidth, it is still impressive that it can deliver 75% of its performance.
Different applications respond differently to the drop in interface bandwidth, and hence you could do with a closer look at the results for each application. Games with lighter texture, shader, and instruction data don't particularly need all 16 lanes, and evidently, in games such as Quake 4, you're able see the accelerator comfortable with even PCI-Express 2.0 x4. Video memory-intensive games will show bigger performance margins. Besides applications, the other important factor is the resolution at which they are being run. At higher resolutions, it pays to have higher interface bandwidth, as it's usually high-resolution textures the GPU is dealing with. Although small, the gaps widen with increase in resolution. However, it is important to realize that even at 1024x768 some applications will see serious differences in performance caused by PCI-Express bandwidth.
Our bottom-line on this subject is that there is every reason to be optimistic when opting for two of these accelerators on motherboards with two PCI-Express 2.0 x16 (electrical x8) slots, because the performance penalty between that and PCI-Express 2.0 x16 (electrical x16) is just too small. Unless you're the quintessential enthusiast and every frame per second increase matters to you, there is no reason to worry about a performance drop on mid-range motherboards, although this is only one of the factors, a main one at that, to contribute to the performance drop. Some motherboard manufacturers are offering a third PCI-Express x16 slot that is electrically x4. The results show that the performance drop isn't as bad as one would imagine, so we will green-signal installing a third accelerator for some 3-way ATI CrossfireX action, or 2-way CrossfireX on entry-level Intel P55 motherboards with the second x16 slot electrically x4 (running in 1.0 mode). If you're crazy enough to mod a PCI-Express x1 slot (by carefully cutting its end to let it seat a PCI-Express graphics card), then the scores should really dishearten you. Buy one of these accelerators now, add one later, and you will have secured yourself future-proofing. "
Is de conclusie gerechtvaardigd dat als een 5870 op een PCI-E 2.0 1x lane nog steeds 76% performance kan leveren, dat een 2e 5850 op een PCI-E16x/4 lanes op de Asus M4A785TD-V EVO ook prima kan presteren?
Of zie ik echt iets helemaal over het hoofd in deze review, bijvoorbeeld dat het alleen voor bepaalde (1156) mobo's geld?
Voor mijn 955BE en 5850 systeem zit ik nu te denken aan de Asus M4A785TD-V EVO.
Dit mobo heeft voor de 2 maal PCI-E 2.0 16x, 16 lanes voor de 1e en 4 lanes voor het 2e GPU slot.
Dit wordt als onvoldoende voor CF gezien, toch? Dat is tenminste wat ik tot nu toe heb begrepen.
Nu las ik net op TechPowerUp een review over de 5870 kaart waarbij deze opeenvolgend werd aangesloten op: Een PCI-E 2.0 8x, een PCI-Express 2.0 4x en zelfs een PCI-Express 2.0 x1
quote uit de review;
"It holds even more relevance to users and potential-users of most socket LGA-1156 motherboards, as this is where 16 lanes from the processor's on-die PCI-E switch are split into two 8 lane links. Surprising as it seems, the Radeon HD 5870 is comfortable, with a mere 2% performance drop overall. PCI-Express 2.0 x4 is where the Radeon HD 5870's discomfort is slightly notable, with a 5% drop, and even more surprisingly, on PCI-Express 2.0 x1, big as it seems, the performance drop is "only" 25% overall. Considering that you rob the card most of its data transfer potential, leaving only a 1/16th of the optimum bandwidth, it is still impressive that it can deliver 75% of its performance.
Different applications respond differently to the drop in interface bandwidth, and hence you could do with a closer look at the results for each application. Games with lighter texture, shader, and instruction data don't particularly need all 16 lanes, and evidently, in games such as Quake 4, you're able see the accelerator comfortable with even PCI-Express 2.0 x4. Video memory-intensive games will show bigger performance margins. Besides applications, the other important factor is the resolution at which they are being run. At higher resolutions, it pays to have higher interface bandwidth, as it's usually high-resolution textures the GPU is dealing with. Although small, the gaps widen with increase in resolution. However, it is important to realize that even at 1024x768 some applications will see serious differences in performance caused by PCI-Express bandwidth.
Our bottom-line on this subject is that there is every reason to be optimistic when opting for two of these accelerators on motherboards with two PCI-Express 2.0 x16 (electrical x8) slots, because the performance penalty between that and PCI-Express 2.0 x16 (electrical x16) is just too small. Unless you're the quintessential enthusiast and every frame per second increase matters to you, there is no reason to worry about a performance drop on mid-range motherboards, although this is only one of the factors, a main one at that, to contribute to the performance drop. Some motherboard manufacturers are offering a third PCI-Express x16 slot that is electrically x4. The results show that the performance drop isn't as bad as one would imagine, so we will green-signal installing a third accelerator for some 3-way ATI CrossfireX action, or 2-way CrossfireX on entry-level Intel P55 motherboards with the second x16 slot electrically x4 (running in 1.0 mode). If you're crazy enough to mod a PCI-Express x1 slot (by carefully cutting its end to let it seat a PCI-Express graphics card), then the scores should really dishearten you. Buy one of these accelerators now, add one later, and you will have secured yourself future-proofing. "
Is de conclusie gerechtvaardigd dat als een 5870 op een PCI-E 2.0 1x lane nog steeds 76% performance kan leveren, dat een 2e 5850 op een PCI-E16x/4 lanes op de Asus M4A785TD-V EVO ook prima kan presteren?
Of zie ik echt iets helemaal over het hoofd in deze review, bijvoorbeeld dat het alleen voor bepaalde (1156) mobo's geld?
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