Pci express splitter

[deslok]

has anyone tried a board such as this one
http://cgi.ebay.com/Dell-POWEREDGE-R710-PCIE-RISER-BOARD-MX843-/270692444242?pt=LH_DefaultDomain_0&hash=item3f0686e852
in a standard(ie non dell poweredge) motherboard to any result? a visual inspection shows it simply breaks the pci slot in half for each of the slots i see no significant supporting logic on the board

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[PatrickHarnett]

Many riser/splitters convert PCIe to PCI.  I've yet to find a device that does PCIe to PCIe splits.  Most useful I ever managed was PCIx to PCIe running GPUs in P3 servers.

[deslok]

thta's why i asked about this one specifically i can see both ends are pci e at least i'm wondering if anyone has tried this or a similar one.

[JoelKatz]

This seems to split an x16 slot into two x8 slots. It doesn't seem to a bridge but a splitter. Obviously, it won't work if you put it in a slot that's already wired for x8. But most chipsets should accept a split of an x16 slot to two x8's. The biggest issue I can see is that it might confuse the BIOS.

[PatrickHarnett]

A quick search shows Joel is right (2 PCIe 8 lanes).

The other issue plugging GPUs into this (bandwidth should not be a problem) will be power draw.  The normal draw is 75W from the mobo, so if you plug in two GPUs it will need possibly double that.  The connections may not be designed to handle that power.  I suspect that's what burned my dell poweredge serve motherboard when I was playing with risers last year - i.e. too much current and slow over-heating = crispy fibreglass and lots of smoke => trash.

[mike678]

A quick search shows Joel is right (2 PCIe 8 lanes).

The other issue plugging GPUs into this (bandwidth should not be a problem) will be power draw.  The normal draw is 75W from the mobo, so if you plug in two GPUs it will need possibly double that.  The connections may not be designed to handle that power.  I suspect that's what burned my dell poweredge serve motherboard when I was playing with risers last year - i.e. too much current and slow over-heating = crispy fibreglass and lots of smoke => trash.

Would something like this fix the power problem?
https://cablesaurus.com/index.php?main_page=product_info&cPath=1&products_id=11

[cicada]

Would something like this fix the power problem?
https://cablesaurus.com/index.php?main_page=product_info&cPath=1&products_id=11

Indeed it would, the molex power adapter allows the card to pull that 75W directly from the PSU, instead of through the motherboard.

You only really need the 1x adapter with molex however, mining is not bandwidth intensive so you don't need all the lanes available to 8x or 16x

[mike678]

Would something like this fix the power problem?
https://cablesaurus.com/index.php?main_page=product_info&cPath=1&products_id=11

Indeed it would, the molex power adapter allows the card to pull that 75W directly from the PSU, instead of through the motherboard.

You only really need the 1x adapter with molex however, mining is not bandwidth intensive so you don't need all the lanes available to 8x or 16x

The 1x is less then a dollar difference in price so it doesn't really change things.

Edit: The site I'm about to post doesn't list prices at least that I see but take a look at this.
http://www.amfeltec.com/products/x4pcie-splitter4.php

[echo2]

hmm wonder how many cards i can cram on 1 motherboard like 20??

[cicada]

hmm wonder how many cards i can cram on 1 motherboard like 20??

I think the current driver is limited to 8 cards.

[mike678]

hmm wonder how many cards i can cram on 1 motherboard like 20??

I think the current driver is limited to 8 cards.

Its 8 on windows. I'm pretty sure on linux its a bit higher.

[IlbiStarz]

hmm wonder how many cards i can cram on 1 motherboard like 20??

I think the current driver is limited to 8 cards.

Its 8 on windows. I'm pretty sure on linux its a bit higher.

No it's 8. It's a driver limitation = Catalyst, not the OS.

[mike678]

No it's 8. It's a driver limitation = Catalyst, not the OS.

Can you cite this? I remember seeing multiple times people saying linux can hold more. This is one of those times.

There are no myths here...

On windows, prior to driver 11.6 only 4 GPUs would work.

GPU does not equal a video card in this context...
Windows will recognize more than 4 video cards just fine... However, you won't be able to use more than 4 GPUs with 11.5 or below.

However, with 11.6 drivers, it looks like there's limited confirmation of 8 GPUs being the new limit.
On Linux there are rumors that the limit is at least 10 GPUs...

[indolering]

They are ~$200/pop 

They must be doing low volume.  Maybe someone from Cablesaurus could do a large order and get the price down to something reasonable?

[Cablesaurus]

We're looking into these as well, from what we've seen so far there's still an 8GPU limit but it may be surpassable.

[indolering]

Can you give any details Cablesaurus?  Looking to get my mobo soon.  If you are about to start selling these splitters at a reasonable price, it will be a mATX with 2 slots.  Otherwise, I will be getting an ATX with the max number of slots I can afford...

Thanks,
-Zach

[Pipesnake]

Just something to consider.  If you have a rig with 2 GPUs go down you freak out a little.  If you have a rig with 8 (or more) GPUs go down....you freak out a lot.

[indolering]

"For 30 units we can do 30% discount."

119.14 + shipping if you have the cash...