Can I use SLI slots as two 8x PCIe slots?

B

BoB-O TiVo

Limp Gawd
Joined
Mar 25, 2004
Messages
147
Hello,

If I end up going hardware RAID, I wanna go PCIe. Can I run an SLI mobo in SLI mode and put an 8x PCIe RAID controller in the second slot?

Thanks,
BoB
 
I see you are a noobie and probably dont know the forums too well yet. So I will lay off this time :) You can use the search up there and all you had to do was search PCIe and bingo.

I have had Multiple threads on this already. I am in the same dillema.

PCIe Threads
http://www.hardforum.com/showthread.php?t=913553&highlight=PCIe
http://www.hardforum.com/showthread.php?t=913512&highlight=PCIe

SCSI RAID Card for PCIe compatibility (a good read) You may not want SCSI but a Controller card none the less is the same deal.

http://www.hardforum.com/showthread.php?t=913228&highlight=SCSI

All in all, it is my conclusion after asking and going thru various things, that it is NOT possible to do this. Because of current motherboard limitations and PCIe lanes.
 
Why can't you? You set the motherboard's connector card for dual cards. All that does is set slots up as 2 x8 PCI-Express slots.

You can use two video cards in their for multi-monitor support. You don't have to use them for SLi.

Your video card will still work with only x8 PCI-Express lanes. Theres no reason why the second slot couldn't except another PCI-Express slot.

If there is I'd like to know.
 
Sir-Fragalot said:
Why can't you? You set the motherboard's connector card for dual cards. All that does is set slots up as 2 x8 PCI-Express slots.

You can use two video cards in their for multi-monitor support. You don't have to use them for SLi.

Your video card will still work with only x8 PCI-Express lanes. Theres no reason why the second slot couldn't except another PCI-Express slot.

If there is I'd like to know.
Click to expand...
If you go into some of my posts up there ^^

You will see I contacted everyone I could. NVidia, DFI, LSI (The SCSI Card) and emailed the Senior Motherboard editor at Anandtech and all came up with the same conclusion. That it would not work with the current NF4 setup. Perhaps with a Bios revision, but the 2 Slots deemed for graphics, only work for that right now. I guess they Figure if you are going to get a SLI mobo, that thats what 99.999% of the people will be using them slots for. Not for someting else.
 
USMC2Hard4U said:
I see you are a noobie and probably dont know the forums too well yet. So I will lay off this time :) You can use the search up there and all you had to do was search PCIe and bingo.
Click to expand...

My problem actually is that I use search TOO much (on other forums). I searched "SLI 8x", trying to be too specific.

Thanks for all the info!
BoB
 
The Asus A8N-E has:

1x PCIe 16x
1x PCIe 1x
1x PCIe 1x
1x PCIe 4x

To my knowledge this is the only socket 939 board out there which actually supports four distinct PCIe devices. I just switched to it actually. I've got a Geforce 8800 in the 16x slot (recent upgrade :D), a wireless LAN card in one of the PCIe 1x slots, a USB/Firewire card in the other and a 3Ware 9650 card in the PCI 4x slot. Works like a charm.

Of course there's no possibility for SLI, but with all the SLI problems in Vista I decided a single more powerful card was a better way to go for now until I do another full system upgarde.

EDIT: The onboard chipset fan on this Motherboard is inadaquet. I highly recommend replacing it before you put the motherboard in. I also necro'd this thread since it took me awhile to find this information and I thought I'd post it for anyone else looking for the same info.
 
I think he's asking about using the PCIe x16 slots for other purposes in the 680i chipset. My guess is, the x16's are still for graphics. However, you should be able to use the x8 for anything you want. It's designed for physics, and people are using it for graphics, so I don't see why a network/RAID/etc card wouldn't work.
 
Hvatum said:
To my knowledge this is the only socket 939 board out there which actually supports four distinct PCIe devices.
Click to expand...
what makes you think that?
abit's KN8 SLI can support 5 (x8, x8, 1,1,1), KN8 Ultra does 4 (x16,1,1,1,) & I'm sure that others can too.
 
USMC2Hard4U said:
If you go into some of my posts up there ^^

You will see I contacted everyone I could. NVidia, DFI, LSI (The SCSI Card) and emailed the Senior Motherboard editor at Anandtech and all came up with the same conclusion. That it would not work with the current NF4 setup. Perhaps with a Bios revision, but the 2 Slots deemed for graphics, only work for that right now. I guess they Figure if you are going to get a SLI mobo, that thats what 99.999% of the people will be using them slots for. Not for someting else.
Click to expand...

So these slots can only be used for graphics? I wouldn't be able to use it for say, physics?
 
An 8x PCIe slot has 8 available "data lanes" for data to travel through.

Most boards have 2 slots that work at 16x, and a few others that are limited to 1x. And maybe a 4x in there somewhere else.

Any PCIe slot can be used with ANY pcie device, provided it supplies enough bandwidth. For example, cramming a 16x PCIe device (GPU) in a 1x slot would terrorize your 3d performance.

You can, however, shove a 1x card in a 16x slot. It won't use any more than 1 of the lanes, but it will work.

So, to answer your question... If you have an available 8x slot, you can cram anything into it, that will use 8 or less lanes. Sometimes, you can even put in a card that uses more lanes, with a speed reduction.
 
BUFF said:
what makes you think that?
Click to expand...
It's really not a question of thinking, it's a question of knowledge. In fact I still 100% back up the assertion that when I made that post I did not know of any other boards which supported four distinct PCIe devices :)

BUFF said:
abit's KN8 SLI can support 5 (x8, x8, 1,1,1), KN8 Ultra does 4 (x16,1,1,1,) & I'm sure that others can too.
Click to expand...

Hmm, I don't think we're thinking about the same things here.

Yes, you can have two graphics cards in the KN8 SLI along with three 1x PCIe cards, but can you have a graphics card in one PCIe 8x slot and a RAID card in the other (going at 4x probably)? If so this would be really interesting, because as far as I know there aren't any Nforce4 motherboards which support this. The PCIe 16x lanes work only for Graphics cards. I know that's how it worked on my old EVGA board.

Either way you're right, you can have four distinct PCIe devices in either of those boards. But I'm not sure that you can have an 8x PCIe GPU along with a 4x RAID card in the SLI (you certainlly can't in the Ultra).
 
Arcygenical said:
So, to answer your question... If you have an available 8x slot, you can cram anything into it, that will use 8 or less lanes. Sometimes, you can even put in a card that uses more lanes, with a speed reduction.
Click to expand...

Unforunately this isn't true for *most* Nforce4 SLI boards. If you put it in SLI mode via a jumper or bios setting you still can't run anything but a GPU in the second PCIe slot. They desinged the SLI mode to just send the same data to both cards when both slots are set to 8x (see above). So unless you want your RAID card to do graphics processing you're SOL.

Apparently the Abit KN8 SLI might support this, but that's up in the air. Either way more modern boards (680i) follow the PCIe spec. as you stated it so this shouldn't be an issue in the future.
 
Hvatum said:
Apparently the Abit KN8 SLI might support this, but that's up in the air.
Click to expand...
you can certainly run a TV tuner card in the 2nd physical x16 (x8 electrical) & I'm fairly certain that it will take a RAID controller card too.
 
BUFF said:
you can certainly run a TV tuner card in the 2nd physical x16 (x8 electrical) & I'm fairly certain that it will take a RAID controller card too.
Click to expand...

Is this your setup? Either way thanks for the confirmation. :)
 
No, but I'm 100% sure that a few people on the abit-USA forum have used the 2nd slot for a TV card.
I think that it's also been used for a RAID controller card but I'm not 100% sure.
 
I have gotten a Dell Perc 4e/DC controller to work in the second SLI slot on both a DFI Lanparty NF4-SLI and a DFI Lanparty CFX3200 motherboard. On the NF4 I was running x8, x8 "SLI" mode. I'm currently running the native x16, x16 on the CFX3200.

I thought the PCIe setup of the CFX3200 would be superior to the NF4. I had heard that the x8/x8 mode of the NF4 was some kind of daisy chain between the second slot and the first slot. I thought this might have been throttling my performance (I have 512Mb RAM cache on my raid card and was expecting higher burst rates)

In practice, there was no disk performance change from the NF4 to the CFX3200. IMHO the NF4 is a nicer board.

I have 2x Fujitsu U320 15K MAU (36Gb) drives in a raid0 array, returns about 150Mb/s (hdtach) on a good day. In general I would rate my experience as not worth the effort, the onboard SATA raid0 I previously had with with a couple of 74G raptors is cheaper and got about 120Mb/s.
 
Hvatum said:
Unforunately this isn't true for *most* Nforce4 SLI boards. If you put it in SLI mode via a jumper or bios setting you still can't run anything but a GPU in the second PCIe slot. They desinged the SLI mode to just send the same data to both cards when both slots are set to 8x (see above). So unless you want your RAID card to do graphics processing you're SOL.
Click to expand...

So is there a board that exists that allows me to have 2 slots that are running at at least 4x speeds for something other than a video card (other than a high end server board)?
 
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