GTX 580 SC SLI 2 16x or 1 16x and 8x?

[iRage]

Hey guys, I have an ASUS Maximus IV with 2 GTX 580 SC Graphic Cards.

The motherboard's manual recommends putting the first card in 16x and the second card in 8x, where as if I had 3 SLI cards, I'd put the first in 16x the second in 16x and the third in 16x! To clarify, I have 3 16x Slots and 2 8x Slots. Now, isn't putting SLI in 2 16x slots faster? Why would ASUS recommend a 16x and 8x setup? Is it a compatibility issue?

I'd appreciate any responses.

 

[1h4x4s3x]

They're both x16 according to the manual.

 

[iRage]

They're both x16 according to the manual.

Sorry, typo, I meant I have an ASUS Maximus IV! The slot closest to the CPU where my first card is, is a 16x, after that 8x, then 16x, 8x, 16x.

 

[1h4x4s3x]

I see, weird indeed. Wish I had an answer but you won't lose much performance anyway. 1-5% maybe?
Have you tried to put it in the not recommended x16 slot?

 

[alcoholbob]

8x does have a slight loss, maybe 2-3%, but when SLI is scaling at what, 70% these days? It's a minimal loss. Now 4x would be a different story.

 

[fffblackmage]

8x does have a slight loss, maybe 2-3%, but when SLI is scaling at what, 70% these days? It's a minimal loss. Now 4x would be a different story.

Not really.

 

[alcoholbob]

Not really.

Not really what?

 

[notty22]

Well sli is never certified for 4x slots.

The placement of the cards recommendation, has something to do with the plx bridge chip that duplexes the extra lanes from the pci-e lanes that are available which are only 16 normally on p67.
Placement of the cards activates electronic switching.
http://www.hardwareheaven.com/revie...extreme-p67-motherboard-review-the-board.html

Beneath the slots we can see the main reason the board is able to offer this connectivity, a PLX branded PCIe controller/switch which adds lanes to those already available on the P67.

edit: I would place them, which would give me the best cooling as long performance seemed correct.

 

[fffblackmage]

Not really what?

It seemed like you expected PCIe x4 to severely limit the benefits of SLI/xfire. There's a slight loss, but it's still not significant, at least for PCIe 2.0.

 

[nanaki333]

rather than start another thread, i'll just hijack here. what's better for a 6970 xfire setup? x16 + x4, or x8, x8? going to retire the s1366 950 and grab a 2600K tonight probably.

 

[CarpeDiem99]

8x and 8x would be better than 16x and 4x for sure.

 

[nanaki333]

thanks much! i'm going to pick this up an MSI P67A-GD65-B3 on my way home. looks like a lot of board for not much money. supports x8 x8

 

[alcoholbob]

It seemed like you expected PCIe x4 to severely limit the benefits of SLI/xfire. There's a slight loss, but it's still not significant, at least for PCIe 2.0.

It looks like 4-5% on average, up to 8% on some. That's certainly a lot more than the 2% upper limit I cited for 8x. 100% to 400% more is a lot to me.

 

[pcm81]

Read this:
http://www.tomshardware.com/reviews/pcie-geforce-gtx-480-x16-x8-x4,2696-16.html

done on 480s, but should still apply to anything else SLI.

 

[fffblackmage]

rather than start another thread, i'll just hijack here. what's better for a 6970 xfire setup? x16 + x4, or x8, x8? going to retire the s1366 950 and grab a 2600K tonight probably.

8x/8x is definitely preferable to 16x/4x.

If you have a i7-950 already, why upgrade to the i7-2600K? Doesn't seem like there's much to gain for the cost. Why not just wait for Ivy Bridge or overclock that i7-950?

 

[stahlhart]

Hey guys, I have an ASUS Maximus IV with 2 GTX 580 SC Graphic Cards.

The motherboard's manual recommends putting the first card in 16x and the second card in 8x, where as if I had 3 SLI cards, I'd put the first in 16x the second in 16x and the third in 16x! To clarify, I have 3 16x Slots and 2 8x Slots. Now, isn't putting SLI in 2 16x slots faster? Why would ASUS recommend a 16x and 8x setup? Is it a compatibility issue?

I'd appreciate any responses.

Isn't tri-SLI 8X/16X/16X on the M4E? Not seeing where you get a 3 x 16X setup here. (?)

I'm running mine in dual VGA (slots 1 and 4) for 2 x 8X. The lower card actually runs a few degrees hotter than the upper one, as I've got an X-Fi in the 4X slot at the bottom, which I think is affecting the air circulation a little. I have a 140mm fan in the side panel directly above them, which drops it down a few degrees. They're never more than 4-5C apart, so I'm not all that concerned about it.