M.2 SSD + SLI How this can affect the SSD or SLI?

[leirbag23]

Hi to everyone... The question is... I have a z170-a motherboard wich several people here recommend, and a i7 6700k, wich has 16 pcie lanes in total.
Im running an SLI with 2 gtx 970 right now, wich performs flawlessly for now.
I was planning to add an M.2 SSD, but it works on PCIE 3.0 x4, i guess it usses the same pcie lanes that graphics cards uses?
how this works exactly?
will i have some down on my sli configuration if i add this M.2 SSD?

There's really little information out there and i guess the opinion of this forum was great until now for many situations.

 

[lunyone]

That is a good question. If I read the Intel spec on the CPU it is:
PCI Express Revision 3.0
PCI Express Configurations ‡ Up to 1x16, 2x8, 1x8+2x4
Max # of PCI Express Lanes 16

So I'm guessing you would have 1 x16 & 1 x4 for the 2 GPU's
and 1 x4 for the M.2 SSD

If I read that correctly. So a total of 3 groups of PCI-e lanes (1 x16, 2 x4)

 

[lunyone]

Or you sell your 2 x 970's and get a GTX 1070 and install the M.2 SSD, so you would have an x8 PCI-e group for the GPU and the SSD Now how is that for reasoning to buy a new GPU??? Lol!

 

[atomicWAR]

depends on what motherboard you have but in some cases it can be issue in others it steals the bandwidth from the PCH and SATA. What motherboard brand/model are you running?

edit oops saw your motherboard in post sorry. You model should be able to run both SLI and M.2. the m.2 uses the SATA and SATA express ports for the PCIe bandwidth.

https://www.asus.com/us/Motherboards/Z170-A/specifications/

if your read full specs you'll see what i mean. though it disables those mentioned ports to function.

 

[lunyone]

I think I was wrong (partially) assuming you have the Asus Z170-A Mobo. It states for the PCI-e slots:
PCI Express 3.0 x16
2 x PCI Express 3.0/2.0 x16 slots (single at x16 or dual at x8/x8 mode)
1 x PCI Express 3.0/2.0 x16 slot* (max. at x4 mode, compatible with PCIe x1 and x4 devices)
* The PCIe x16_3 slot shares bandwidth with SATA6G_56. The PCIe x16_3 is default set at x2 mode.

** Edit **
Here is the Storage info:
SATA 6Gb/s
6 x SATA 6.0 Gb/s ports (gray, 2 from SATA Express)
SATA Express
1 x SATA Express port (compatible with 2 x SATA 6.0 Gb/s ports)
M.2
1 x M.2 Socket 3 with M Key**, type 2242/2260/2280/22110 storage devices support (both SATA & PCIE mode)***
** Supports PCIE RAID configurations via onboard M.2 and PCIex16_3.
*** M.2 shares SATA mode with SATA Express. Change this item before installing M.2 SATA devices.

So maybe you should have 2 x8's for the GPU and disabling the SATA Express gives you full x4 on the M.2 slot??

 

[leirbag23]

That is a good question. If I read the Intel spec on the CPU it is:
PCI Express Revision 3.0
PCI Express Configurations ‡ Up to 1x16, 2x8, 1x8+2x4
Max # of PCI Express Lanes 16

So I'm guessing you would have 1 x16 & 1 x4 for the 2 GPU's
and 1 x4 for the M.2 SSD

If I read that correctly. So a total of 3 groups of PCI-e lanes (1 x16, 2 x4)

Actually im reading and everyone says that it depends on the chipset, cos z170 has 20 pcie lanes 3.0 bla bla bla... but if the cpu has only 16, i really cant understands how this interacts with the mobo and the chipset for the "data interaction", while using of course 2 gpus...

My build looks awesome... will not change my 2 gtx 970 at all! at least not for a year!

 

[leirbag23]

depends on what motherboard you have but in some cases it can be issue in others it steals the bandwidth from the PCH and SATA. What motherboard brand/model are you running?

edit oops saw your motherboard in post sorry. You model should be able to run both SLI and M.2. the m.2 uses the SATA and SATA express ports for the PCIe bandwidth.

https://www.asus.com/us/Motherboards/Z170-A/specifications/

if your read full specs you'll see what i mean. though it disables those mentioned ports to function.

Yes yesss, i already see what you're saying... but there's no info about how it actually works, not even tells you if at 1x 2x 4x... nothing...
From Asus specifications:

1 x M.2 x4 Socket 3, *2, with M Key, type 2242/2260/2280/22110 storage devices support (both SATA & PCIE mode)*3

*2: Supports PCIE RAID configurations via onboard M.2 and PCIex16_3.
*3: M.2 shares SATA mode with SATA Express. Change this item before installing M.2 SATA devices.

I guess that i should put this on "SATA" mode, if i dont, it will actually shares the bandwidth with GPUS, but i can actually knows if SATA MODE will use my SSD at the "best speed rate" cos it does not says.

 

[lunyone]

That is a good question. If I read the Intel spec on the CPU it is:
PCI Express Revision 3.0
PCI Express Configurations ‡ Up to 1x16, 2x8, 1x8+2x4
Max # of PCI Express Lanes 16

So I'm guessing you would have 1 x16 & 1 x4 for the 2 GPU's
and 1 x4 for the M.2 SSD

If I read that correctly. So a total of 3 groups of PCI-e lanes (1 x16, 2 x4)

Actually im reading and everyone says that it depends on the chipset, cos z170 has 20 pcie lanes 3.0 bla bla bla... but if the cpu has only 16, i really cant understands how this interacts with the mobo and the chipset for the "data interaction", while using of course 2 gpus...

My build looks awesome... will not change my 2 gtx 970 at all! at least not for a year!

Yeah it is a bit confusing, I don't know myself so I'm just guessing, but it could be one of those things that you won't know how your performance is until you install the M.2 SSD.

 

[leirbag23]

I think I was wrong (partially) assuming you have the Asus Z170-A Mobo. It states for the PCI-e slots:
PCI Express 3.0 x16
2 x PCI Express 3.0/2.0 x16 slots (single at x16 or dual at x8/x8 mode)
1 x PCI Express 3.0/2.0 x16 slot* (max. at x4 mode, compatible with PCIe x1 and x4 devices)
* The PCIe x16_3 slot shares bandwidth with SATA6G_56. The PCIe x16_3 is default set at x2 mode.

** Edit **
Here is the Storage info:
SATA 6Gb/s
6 x SATA 6.0 Gb/s ports (gray, 2 from SATA Express)
SATA Express
1 x SATA Express port (compatible with 2 x SATA 6.0 Gb/s ports)
M.2
1 x M.2 Socket 3 with M Key**, type 2242/2260/2280/22110 storage devices support (both SATA & PCIE mode)***
** Supports PCIE RAID configurations via onboard M.2 and PCIex16_3.
*** M.2 shares SATA mode with SATA Express. Change this item before installing M.2 SATA devices.

So maybe you should have 2 x8's for the GPU and disabling the SATA Express gives you full x4 on the M.2 slot??

Yeah, i dont actually know, i guess i'll contact Asus support before trying cos if not, it's a waste of money... it's not clear anywhere how it will actually works and at wich speed in this case.

 

[lunyone]

Yeah that is going to be your best bet. Personally I'd probably either stick with 1 GPU or just use a regular SATA SSD (I know they read slower than the PCI-e version, but just saying).

 

[Angel_Cortes]

Hi to everyone... The question is... I have a z170-a motherboard wich several people here recommend, and a i7 6700k, wich has 16 pcie lanes in total.
Im running an SLI with 2 gtx 970 right now, wich performs flawlessly for now.
I was planning to add an M.2 SSD, but it works on PCIE 3.0 x4, i guess it usses the same pcie lanes that graphics cards uses?
how this works exactly?
will i have some down on my sli configuration if i add this M.2 SSD?

There's really little information out there and i guess the opinion of this forum was great until now for many situations.

I'm still trying to figure that out myself. I do have one of those M.2 ssd, and my second gpu is not even recognized as a device (2x GTX680, one in 16 lane x16, and the other in 16 lane x8) the x8 doesnt work for some reason. if your board has an M.2 slot in addition to the PCIe then go right ahead. its not occupying a slot. Now, how if affects the system is my threshold in knowledge about the PCIe speed negotiations.