crossfire 8x8 vs 16x16

darckeen

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Whats the realworld difference between the 8x8 available on the p45 and the 16x16 available on the x48? Also what cards actually benefit from getting 16x16 in crossfire or will all the currently availble radeons be ok at 8x8?
 

ausch30

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I haven't seen any reviews but you have to remember that 8x PCI-E 2.0 is the same as 16x PCI-E so the P45 still has a lot of bandwidth available. I remember seeing a Tom's article a while back where only the very fastest cards (8800GTX and Ultra at the time) saw any difference in performance between PCI-E 8x and 16x so with PCI-E 2.0 8x being the equivalent of PCI-E 16x I would imagine that anything but the X2 cards would not see a difference. With that said though if you plan on keeping the system for a while and just upgrading the video card you might want the added headroom of PCI-E 2.0 16x
 

darckeen

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So essentially what your saying is that any card that isn't bottlenecked at PCI-E 1.1 in a single card is not going to be bottlenecked in a 8x8 PCI-E 2.0 setup. As from what I've heard, not many cards really push the PCI-E 1.1 bandwith atm. The best card I'm willing to buy at the moment is a 4850, will that hit the PCI-E 1.1 limit?
 

ausch30

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That is what I'm saying and I haven't seen the benchmarks but i would say that the 4850 wouldn't be close to filling the PCI-E 2.0 8x bandwidth.

If your only looking for the 4850 why are you worried about that? Most p45's are 16x with one card and either 16x and 4x or 8x and 8x with 2 cards so if you are only getting 1 card you will still have 16x.
 

V3NOM

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well two 8800GT's in sli on the x8 x8 evga 750i ftw is no difference in performance compared to the same setup on a 780i/790i.
 

shaneire

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I have two 4870s on the P45 and although its only x8 link the fact its PCIe 2.0 should have enough bandwidth, but I do get the feeling I'm underperfoming. I regret not getting a x16 link mobo now.
 

cal8949

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