SLI 2x16x versus 1x16x+1x8x PCI-E

gunnarhx

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May 28, 2009
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SLI experts out there!! Please advise.

Ok, so I upgraded my MB to an Asus M4N82( two PCI-E 16x and one 8x), earlier I had an MB with only one PCI-E 16x slot.
The main reason was that for my work, I need to run an SAS controller card, which needs PCI-E 8x, so I got that covered.
A second reason is that I wanted to explore SLI, I have one GTX 260, so now I got room for another one.

Obviously, I'd like to populate the two 16x with the two GTX 260 and keep the SAS card in the 8x (the 8x is in between the two 16x). Makes sense, right? Now I realize that the SAS card got the components on the opposite side on the card compared to the GTX 260, therefore the above population is impossible, due to space constraints.

But I think the following is possible:
- SAS card in 16x (components facing CPU)
- GTX 260 in 8x (facing opposite direction)
- GTX 260 in 16x (facing opposite direction)

Now question:
- Will this setup lower gaming speed (theoretically vs practically)???
- And also, this should work on my Asus, will it? That is, I should be able to use 8x+16x, right? This is a tri-SLI board afterall.

Thanks
 

gunnarhx

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I read the manual, and they tend to use wordings such as 'recommended' when referring to which pcie slots to use for graphic cards. They 'recommend' to use blue (16x) for graphics and other cards for 8x.

Does anyone know if first slot needs to be graphics??
 

gunnarhx

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Yes, I would like to do that too.

But as mentioned, the sas card (supermicro, lsi-based) has the components on the 'wrong' side of the card making it impossible to place the sas card in the x8 slot.

So I guess the questions are:
- can I put graphics cards in x8 and x16, neither of which is first pci-e slot?
- If so, would I experience any significant performance degradation compared to 'ideal' 2x16x?

Thanks