AsRock z170 PCIe lanes?

kaigen

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I understand from another article on Tom's hardware that the skylake 6700k&6600k processors have "20" lanes, 16 truly available and 4 "reserved" for storage. from what I read it is up to motherboard manufacturers how these are divided (M.2 more USB 3.0 ect)

I would like to use two graphics cards in Sli, then also use the Intel 750 NVMe, PCIe storage solution. I want to make sure that this will function, Sli only works with x8/x8 lanes (crossfire can do less) and the NVMe will want x4 lanes. It should add up but I can't tell if my board of choice will support it; I want to use an AsRock Extreme 7 for the system build.
 

junkeymonkey

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as long as you use the 2 lanes that are wired to the cpu-- when you use a pcie slot [3] it runs off the chipset and then shared with the pic-e [2ed] and you then get the 8x8x4 [normal ]

if you can find a review like this that better explains ''slots'' it may help some ??

my board
http://www.hardwaresecrets.com/asrock-z87-extreme6-motherboard/2/

every board can be ''wired'' differently so its a good thing to know as you want to

like I stated in the toms review posts you would think intel could overcome this by now ?? amd been offering 2 full x16 ???

NVidia specs - sli for each lane to be x8 min. so as long as you get 2 pci-e at x8 each your good

one thig I see at asrock is they state quad sli on these boards ??? hows that work out asrock ???

''Supports NVIDIA® Quad SLI™ and SLI™

http://www.asrock.com/mb/Intel/Z170%20Extreme6/?cat=Specifications
 

junkeymonkey

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as long as you use the 2 lanes that are wired to the cpu-- when you use a pcie slot [3] it runs off the chipset and then shared with the pic-e [2ed] and you then get the 8x8x4 [normal ]

if you can find a review like this that better explains ''slots'' it may help some ??

my board
http://www.hardwaresecrets.com/asrock-z87-extreme6-motherboard/2/

every board can be ''wired'' differently so its a good thing to know as you want to

like I stated in the toms review posts you would think intel could overcome this by now ?? amd been offering 2 full x16 ???

NVidia specs - sli for each lane to be x8 min. so as long as you get 2 pci-e at x8 each your good

one thig I see at asrock is they state quad sli on these boards ??? hows that work out asrock ???

''Supports NVIDIA® Quad SLI™ and SLI™

http://www.asrock.com/mb/Intel/Z170%20Extreme6/?cat=Specifications
 

kaigen

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I'm fairly aware of the idea of "slots", the problem comes from how they are listed out:

- 3 x PCI Express 3.0 x16 Slots (PCIE2/PCIE4/PCIE6: single at x16 (PCIE2); dual at x8 (PCIE2) / x8 (PCIE4); triple at x8 (PCIE2) / x8 (PCIE4) / x4 (PCIE6))
- 3 x PCI Express 3.0 x1 Slots (Flexible PCIe)
- Supports AMD Quad CrossFireX™, 3-Way CrossFireX™ and CrossFireX™
- Supports NVIDIA® Quad SLI™ <(defiantly weird) and SLI™
- 15μ Gold Contact in VGA PCIe Slot (PCIE2)

The first line tells me that there are 3 pcie slots yes but then says the brake down if three are occupied is x8/x4/x4 which would burn the sli. Then I come down a line and talks about the pcie x1 which I guess is just that? x1 lane?
At first glace this tells me that this board will not work with what I want. where as the msi's z170 board line up ( http://www.newegg.com/Product/Product.aspx?Item=13-130-873 ) has it listed out simply 8/8/x4 so this one will work? It seemed odd to me that only one manufacturer would not have all 20 lanes available. As all of them say in some fashion that it will run x8/x8/x4.

wait though now that I look again this one has "triple at x8 (PCIE2) / x8 (PCIE4) / x4 (PCIE6))" that's what I'm looking for... then why did I, *looks at newegg specifications* there it is:

4 x PCI Express 3.0 x16 Slots (PCIE2/PCIE4/PCIE6: single at x16 (PCIE2); dual at x8 (PCIE2) / x8 (PCIE4);
triple at x8 (PCIE2) / x4 (PCIE4) / x4 (PCIE6). PCIE3: x4 mode)
PCI Express x1
1 x PCI Express 3.0 x1 Slot (PCIE5) (Flexible PCIe)
1 x PCI Express 2.0 x1 Slot (PCIE1)

Triple is listed out incorrectly on the newegg spec sheet... thanks for your time I think this answers my question.
I went to the AsRock website spec page because of the link junkeymonkey provided, thanks
 

junkeymonkey

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the lanes are a cpu limitation with these typ of chips unlike the chips that go on a ''X'' board they got more lanes built into them and the boards come with a ''PLX'' chip to overcome that so with them you can get up to 4 pci-e at x16

intel is not as straight forward as amd you can find intel board that cant do sli cause the slots cant do the x8 by x8 and only good for x-fire that requires x4 at the slot

if you liik at that web site at the motherboard reviews I posted and look at different boards in z 87/97 and read the ''slots'' part to see how there configured on the boards bottom line is you got to have 2 pci-e lanes that run through the cpu to get true x8 by x8 - through the chipset it all shared from x8 down as you load them up

like it says for the Z97 killer under the slot part of its review

Only the first PCI Express x16 slot is controlled by the CPU, so it is based on the 3.0 specification and doesn’t share bandwidth with other slots, i.e. it always works at x16 speed. On the other hand, the second PCI Express x16 slot is controlled by the chipset (so it is based on the 2.0 specification) and shares bandwidth with the PCI Express 2.0 x1 slots: if one of them is used, the second PCI Express x16 slot works only at x2 speed, not x4.
Read more at http://www.hardwaresecrets.com/asrock-fatal1ty-z97-killer-motherboard/#tFJ3j2B58Jip917l.99


all z boards and not alike and for sli you want 2 slots at x8 through the cpu

its crazy - but important to know
 

kaigen

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Looks like AsRock updated their spec sheet;

- 4 x PCI Express 3.0 x16 Slots (PCIE2/PCIE4/PCIE6: single at x16 (PCIE2); dual at x8 (PCIE2) / x8 (PCIE4); triple at x8 (PCIE2) / x4 (PCIE4) / x4 (PCIE6). PCIE3: x4 mode)
- 1 x PCI Express 3.0 x1 Slot (PCIE5) (Flexible PCIe)
- 1 x PCI Express 2.0 x1 Slot (PCIE1)
- 1 x Half-size Mini-PCI Express Slot


Now it has the same confusing blurb as the Newegg one. Back to my question then, PCIE3 says "x4 mode" I don't know what that means if it is populated with an NVM-E does it not count for the slots lane brake out? Or will my sli go down when I do that?

This is the lane brake out for MSI;

3 x PCIe 3.0 x16 slots (support x16/x0/x4, x8/x8/x4 modes)

it has it clearly that it will do x8/x8/x4 for three populated slots, I would just get an MSI board (because they all list it out that clearly) but I already purchased my board and it'd be a shame not to get want I wanted just because the spec sheet is confusing.
So let me know if anyone has an idea of what is going with these confusing specs.

Thanks;
 

junkeymonkey

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I assume your still talking about the exe 7 ?/

Z170 Extreme7+

thing is the cpu only has so many lanes - ''' On the PCI-Express Graphics allocation side, the Skylake processors will have sixteen PCIe 3.0 lanes to use for directly attached devices to the processor, similar to Intel's previous generation processors. These can be split into a single PCIe 3.0 x16, x8/x8 or x8/x4/x4 with basic motherboard design. (Note that this is different to early reports of Skylake having 20 PCIe 3.0 lanes for GPUs. It does not.)


so the best you can get with out going with a ''X'' board is 1@16 2@ 8x8

and just like I said above with the rest of the slots on the chipset [x4] '' With this, SLI will work up to x8/x8. If a motherboard supports x8/x4/x4 and a PCIe card is placed into that bottom slot, SLI will not work because only one GPU will have eight lanes. NVIDIA requires a minimum of PCIe x8 in order to enable SLI. Crossfire has no such limitation, which makes the possible configurations interesting. Below we discuss that the chipset has 20 (!) PCIe 3.0 lanes to use in five sets of four lanes, and these could be used for graphics cards as well. That means a motherboard can support x8/x8 from the CPU and PCIe 3.0 x4 from the chipset and end up with either dual-SLI or tri-CFX enabled when all the slots are populated.'''


I don't know why asrock list's thing like that ? may need to e-mail support to see what they say ???

I don't get it


did you down load the manual to see how its was listed in it ??

• 4 x PCI Express 3.0 x16 Slots (PCIE2/PCIE4/PCIE6: single
at x16 (PCIE2); dual at x8 (PCIE2) / x8 (PCIE4); triple at x8
(PCIE2) / x8 (PCIE4) / x4 (PCIE6). PCIE3: x4 mode)

from the manual its correct I would think on that board 1- @ 16x ..2 -@ 8x8.. 3 -@ 8x8x4 .. 4-@ 8x8x4x4 [??] then you got to page 21 of the manual under '' PCIe Slot Conigurations '' it shows that pci-e slot 3 is not available ??

if it comes up as N/A then what is it there to do ??

ftp://66.226.78.21/manual/Z170%20Extreme7+.pdf

 

junkeymonkey

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but the PCIe layout needs a bit of explaining. The top full length slot is x16, which is then followed by a PCIe 3.0 x4 from the chipset. Then we get a PCIe 3.0 x8 from the CPU, and then a PCIe 3.0 x4 from the CPU as well. This technically gives an x8/x4/x4 arrangement from the processor, but with that chipset based slot in the middle between the main x8/x8, we can get a two-card SLI configuration plus another full length single slot device between them without breaking SLI

http://www.anandtech.com/show/9485/intel-skylake-z170-motherboards-asrock-asus-gigabyte-msi-ecs-evga-supermicro/3

thing is the cpu has only 16 lanes to work with and it seems that's to only way they can get a descent lane configuration -- looks like a intel limitation -

the chipset has 20 lanes

http://www.anandtech.com/show/9483/intel-skylake-review-6700k-6600k-ddr4-ddr3-ipc-6th-generation/3


I just figure with intel just get 1 powerful card and give it all the cpu to play with [opinion]
 

junkeymonkey

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I understand -- when I first went intel with a z87 this was a head scratcher to me as well - not as straight forward a amd .. and all say z boards can be configured differently on this

thing is amd rund all off there chipset [I think it will do 42 lanes nothing off the cpu] intel has 16 on the chip[cpu] 20 on the chipset so it comes down to how things are divided up

and this is about the best answer explained here I can find

http://www.anandtech.com/show/9483/intel-skylake-review-6700k-6600k-ddr4-ddr3-ipc-6th-generation/3

I assuming in order to keep sli as said is in a 3 card set up one card is on the chipset to keep things at 8x8 if not with i5 or i7 haswell/skylake it would be the 3 way 8x4x4 due to the ''CPU'' 16 lane limitation

so the total cpu and chipset pci-e lanes is 36 16 for the chip 20 for the chipset - but how each manufacture wires this up to work is I guess up to them and how they feel is the better way ??

also look ay how many ''Z'' 87-97-and maybe 170 boards that don't do sli at all .. and are just wired for 8x4x4 [crossfire supported only]

I wish I could explain it better but ..........
 

junkeymonkey

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sorry I ment from here as well [ asrock z 170 exe 7 review ]

http://www.anandtech.com/show/9485/intel-skylake-z170-motherboards-asrock-asus-gigabyte-msi-ecs-evga-supermicro/3
as said
but the PCIe layout needs a bit of explaining. The top full length slot is x16, which is then followed by a PCIe 3.0 x4 from the chipset. Then we get a PCIe 3.0 x8 from the CPU, and then a PCIe 3.0 x4 from the CPU as well. This technically gives an x8/x4/x4 arrangement from the processor, but with that chipset based slot in the middle between the main x8/x8, we can get a two-card SLI configuration plus another full length single slot device between them without breaking SLI.

as I see it the only way any board for any manufacture on this has to pull the extra x8 off the chipset in order not to brake sli compatibility.. the chip[ cpu ] alone cant do it
 

kaigen

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So the folks on the AsRock forums had this for us:

"The PCIe 3.0 lane specs for the ASRock Extreme7+ look correct to me, due to a new feature of the Z170 chipset.

For the first time the Z170 chipset provides up to 20 PCIe 3.0 lanes. So the PCIE3 slot can provide four PCIe 3.0 lanes independently of the CPU:

http://ark.intel.com/products/90591/Intel-GL82Z170-PCH

This new feature of the Z170 chipset is a significant change, and I'm surprised it is not as well known as it should be IMO.

But I will say that the specs do not make that clear, so I understand why you are asking about this."


Seems to basically confirm what you were just saying there are another x4 pci-e lanes off the chip set.

So the last question is, is "PCIE3" the third slot down on the board or the second like between the two cards?

 

axlrose

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Sorry to dig up an old post, but I am looking into this board...

http://www.newegg.com/Product/Product.aspx?Item=N82E16813130870

Are z170 boards limited to 20 lanes? This board boasts 2 M.2 slots, but if that takes up two lanes of 4x each, that means I can't even run a single card at 16. It also means I can't run two cards at 8x 8x. Does that seem right? I feel like it boasts something special in two M.2 lanes but at the cost of only being able to run a single 8x video card then???

Thanks.
 

trag19

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This thread came up when I was searching for a similar answer regarding the Asrock Z170M Extreme4. I think this thread covers most of what I'm about to write, but I'm not sure it's clearly presented.

The Skylake CPU provides 16 lanes. The Z170 chipset provides 20 lanes.

On the Z170M Extreme4 and probably on the Exreme7 as well, two slots share the CPU lanes. These are the slots that can be 16X alone, or 8X each. One more slot has chipset lanes and this is the third video card slot. It's not clear to me whether this third slot has 4X chipset lanes available, or 16X chipset lanes possible to be used. Why call the third slot a X16 slot, unless there are actually 16 lanes available in it?

On the Z170M Extreme4 motherboard, the specifications are similar to the Extreme 7, stating:

- 3 x PCI Express 3.0 x16 Slots (PCIE1/PCIE3/PCIE4: single at x16 (PCIE1); dual at
x8 (PCIE1) / x8 (PCIE3); triple at x8 (PCIE1) / x8 (PCIE3) / x4 (PCIE4))*
- 1 x PCI Express 3.0 x1 Slot (Flexible PCIe)

So the Z170M Extreme4's slots 1, 3 and 4 correspond to the Extreme7's 2, 4 & 6. The Z170M Extreme4 is a Micro ATX board, so it only has four slots instead of seven.

According to the email I had from Asrock Support:

"If not any card installed on PCIE3 slot that PCIE1 is running at 16x mode.

PCIE 1 and 3 are using CPU PCIE lane.

PCIE4 is using chipset PCIE line."



 

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