CF/SLI @x8x8 vs x16x16

[Karl_the_n00b]

Hey guys.

Been trying to look into this but the only thing I found was from 2007.

Basically I'm trying to find figures of the performance difference between CF and SLI running at x8x8 and x16x16. Sandy bridge specifically if it makes a difference though I doubt it.

Some people say its marginal

Some people say you must have a UD7 or rampage in case you ever do want to run CF/SLI in the future because the of the performance difference between duel x8 and duel x16.

Nobody supply's figures though.

Has anybody got any links to some resent figure's on this so I can make an informed decision for a change?

Thank you in advance, your a sanity saver.

 

[jay2tall]

Here is one using (2) GTX480's and a x58 chipset mobo. I presume it would be similar on a Sandy bridge mobo. The throughput of the bus wouldn't change as they are PCI-E 2.0.

http://www.hardocp.com/article/2010/08/23/gtx_480_sli_pcie_bandwidth_perf_x16x16_vs_x8x8/1

 

[Karl_the_n00b]

That is just what I was after, thank you very much!

Personaly I can't see how it would make a diffrence between the X58 and the P67 as at the end of the day isn't it the same bandwidth on both boards? If this is wrong or even if I'm using the term bandwidth wrong then please let me know.

Thanks alot guys.

 

[jay2tall]

The bus has the same bandwidth for PCI-E 2.0 on any motherboard. There are older articles that showed a performance hit when you ran x8 x8 on PCI-E 1.1 as opposed to 2.0.

PCI-E 1.1 was 250 MB/s per lane vs 500 MB/s per lane on 2.0. Most cards can run fine on PCI-E 2.0 x8 with the exception of maybe highend dual GPU cards. It's all in the amount of bandwidth you have available to the bus.