Can a SLI slot be used for PCIe-1x DAQ?

[MEDeval]

Can one of the two PCIe slots on a SLI motherboard be used as a PCIe-1x slot?

Creig (golden Member) indicated that the upcoming DFI LanParty board is supposed to be SLI compatible with all PCI-E slots, one of which can be set at either 16x or 8x, the next one capable of 8x or 1x. I have seen photos of the LanParty board and it appears to have to PCIe-16x slots and two PCIe-1x slots. Other SLI motherboards appear to only have two 16x slots.

I hope to have a PCIe-1x slot available for a data-acquisition-card (DAQ). Later, I hope to use the SLI configuration to render the data.

Will any of the first run SLI motherboards have a dedicated PCIe-1x slot in addition to the PCIe-16x slots?

 

[MEDeval]

I thought it was a reasonable question. I know the smart people in the AnandTech forums must know the answer.

I love AnandTech. I was reading in Forum Issues and I was dismayed by the 1000 post minimum concept. As an expectant father, 55hr/wk, just moved, caretaker of both parents, I do not have much time to post replies. How can I contribute to the community?

 

[Thermalrock]

this is a disaster. they were suppose to have 20 lanes 1x 16x or 2x 8x and 4x 1x. i thought theyd settle for 2x pci-e 1x and 2 crappy pci. now it seems like the asus and msi both dont feature a single pcie 1x slot but 4 crappy pci slot which i couldnt care less for. this is sad.

 

[McArra]

I don't relly know how it will end. I think PCI-E 1x are those tiny ones, designed for sound cards, SCSI ans SATA II controllers etc. And the ones for the graphics are the 8x and 16x, which are quite bigger and specially designed for graphic cards. I'm not completely sure, but I think that's the way it goes.

Welcome to Anandtech!!

 

[piroroadkill]

I'm guessing you know what PCI and PCIe slots look like, the ones for graphics cards are usually 16 lane PCIe slots, and the 1 lane PCIe slots are tiny, similar in size to the CSR or AMR risers of old.

You can use a PCIe 1 lane card in a 16 lane slot just fine, as I understand it, but obviously not the other way round.

In SLI configurations, you get 2x 16 lane PCIe slots, but although they are 16 lane size, electrically they only have 8 lanes a piece, but this has no appreciable impact on performance due to even 8 lanes being massively higher than the bandwidth any current graphics card could saturate.

 

[gobucks]

I don't think most card will physically fit into a x16 slot, but we'll see, I guess. As for the SLI boards, the one I've seen from Asus has 2 x1 slots in between the x16 ones, a pretty good idea if you ask me (so long as PCIe cards don't end up being too wide to fit under the SLI bridge chip. I guess we'll see, though.

 

[Concillian]

It's unclear.

Yes, a 1x device will physically plug into a 16x slot and it is SUPPOSED to work if you pluug a lower end card into a higher end slot (like a 1x card into a 16x slot). HOWEVER, how I have seen the implementation is that the slots are either 8x/8x or 16x/disabled.

You can probably run them in 8x/8x mode and run your 1x and a video card as 8x.

However, why go for an SLI board if that's what you want to do. I've seen non-SLi boards that are looking to have a 16x + 2-3 1x slots.

 

[jkresh]

I believe asus's sli board has 2 pci-e 1x slots along with the 16x,8x and 3 pci slots (thats what the say anyway) , so unless you need 3 or more 1x cards, you should be fine.

 

[Hikari]

I'd think so. I know one of the boards (or is that all?) lets you switch between 8x and 8x or 16x and 1x on those slots.

 

[Thermalrock]

Originally posted by: Hikari
I'd think so. I know one of the boards (or is that all?) lets you switch between 8x and 8x or 16x and 1x on those slots.

yes the asus site says either 8x + 8 x or 16x + 1x. this is great

 

[Nyati13]

Originally posted by: piroroadkill

In SLI configurations, you get 2x 16 lane PCIe slots, but although they are 16 lane size, electrically they only have 8 lanes a piece, but this has no appreciable impact on performance due to even 8 lanes being massively higher than the bandwidth any current graphics card could saturate.

To be nit-picky.. both slots are electrically still 16x (they still each provide the full 16x wattage needed by the graphics card. They become 8x data lanes slots when the SLI function is enabled.

Signaling, and electrical supply are not the same thing.

 

[alexkraemer]

I'm interested in this because Tekram has released PCIe x4 SATA RAID cards, however none of the SLI motherboards come with x4 slots. Hence, can the second SLI slot be used for a x4 or up to x8 non-video card? (These babies will come out soon)