z170a board - Pciex16 or pciex8 slot expander for more than one riser card on the same pciex16 or x8 slot?

markm75

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Im using a z170a motherboard for mining and as a server (win 10 though), i have limited slots because i have a few nvme cards in it at the same time.
I want to say i thought this was possible, but there is a way to break out the pciex16 or x8 slot into multiple risers from the same slot?

Im not sure which device it is though, i think a card goes in there and then usb cables from my existing riser cards i already bought (IE: they dont have to be the same brand/set, it can be the riser card from another pciex1 + riser card set)?

I thought maybe this $30 card on amazon, but it appears to only be a pciex1 type card, how could that expand into 4? (i really only need one that expands to two)? I would have expected at least a x4 type card?

https://www.amazon.com/BGNing-Expre...words=pciex16+to+riser&qid=1623344757&sr=8-24
(one review says wrecked the pc)

How reliable are these adapters if the right one? (my other option is to just drop the one nvme and combine a larger one from the one I drop freeing up the slot).
EDIT: unsure if this would work on a motherboard that doesnt support bifurcation like the z170a.

This would be simpler if i could use 2 nvme on one pciex16 or x8 slot and not need this, but this motherboard doesnt support 2 in one slot for nvme dual slot cards at least (or maybe find some usb external nvme option).

Any thoughts?
 
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GiGaBiTe

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I want to say i thought this was possible, but there is a way to break out the pciex16 or x8 slot into multiple risers from the same slot?

Your motherboard would have to support PCIe Bifurcation for this to work.

The adapter that you listed is is basically a PCIe to PCIe bridge or switch that breaks a single lane out into four separate lanes that all share the same bandwidth. It doesn't do bifurcation. These types of bridge chips have been common for a long time, and are often used on motherboards to have more PCIe lanes than the CPU/chipset supports by spreading fewer high bandwidth lanes into more shared bandwidth lanes.
 

markm75

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Your motherboard would have to support PCIe Bifurcation for this to work.

The adapter that you listed is is basically a PCIe to PCIe bridge or switch that breaks a single lane out into four separate lanes that all share the same bandwidth. It doesn't do bifurcation. These types of bridge chips have been common for a long time, and are often used on motherboards to have more PCIe lanes than the CPU/chipset supports by spreading fewer high bandwidth lanes into more shared bandwidth lanes.

So the card, if doesnt do bifurcation might actually work? I guess only one way to tell/try to be certain. My only concern was risk to the gpu's (ie: trying to go to 2 cards from the card).
 

GiGaBiTe

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The card you linked to doesn't do bifurcation. It's a PCIe to PCIe bridge, or a PCIe switch. Hard to know which it is since there's a heatsink on the IC.

Just think of a network router, you have the internet coming in, split out to all devices plugged into it. All devices share the bandwidth of the internet connection. The same happens on the card we're talking about, but it's PCIe instead of Ethernet.

Normally it would be a horrible idea to do this with video cards, but if all you're doing is mining with them, the bandwidth requirements are so low that it doesn't matter much.
 

lopoetve

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That's ~basically~ the cost of a PLX chip, so it could be either - but margins would be nonexistent if it was a full PLX implementation.
 

markm75

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Update, the riser converter/multiplier card worked fine, just not in the pciex16 slot.
When i had it in the pciex16 slot it gave me a b1initializelibrary failed 0xc00000bb error.

i tested this multiplier card with 3 gpus attached and was still able to have two pciex4 ssd nvme cards in the system with no issue (also have a gpu in another slot and will be adding one more gpu to another free slot as a result).
 
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