SM951 M.2 and Intel 750 on Z170?

[Chris22963]

About to start a new PC build based on Skylake:

Asus Z170 Deluxe
i7-6700K
GeForce 780 (may upgrade this but no SLI plans)
Intel 750 PCI-E SSD (400 GB)

Full parts list at uk.pcpartpicker.

It occurs to me that the OS and apps will take a big chunk out of the 750's 400 GB, so I'm now thinking I might get a 256 GB SM951 for booting Windows and installed applications, leaving the 750 for the other things I need fast storage for (VMs and databases).

However, the PC will also be used for gaming, albeit not SLI.

Given the 20 PCI-E lanes supported by the i7-6700K will the two PCI-E SSDs plus an x16 graphics card cause a bottleneck?

Even if it does force the graphics card to run at x8, am I right in thinking that for all practical purposes that will have no practical performance impact on single-GPU gaming? As above, I currently have a GeForce 780 but considering upgrading to 970.

Cheers..

 

[maddogchen]

i might be wrong, but I think you're fine.

The i7-6700k runs 20 but the Z170 chipset runs another 20. So the graphics would run through the i7 and the storage through the Z170.

Edit: I found this:

Z170 offers a wider range features, you will see support for up-to six SATA3 devices, support for M.2., U2 but also USB 3.1 is going to be a common thing you will see with these motherboards. Z170 will be the platform used by you guys, you can expect PCI Express 3.0 with 16 links controlled by the processor and another 8 to 4 links through the PCH. Interesting to know is that the processor will drive 16 PCI-Express gen 3.0 lanes and then the PCH will drive another 20 PCI-Express gen 3.0 lanes. So your SATA / M2 devices will not hog valuable PCI-Express lanes from the processor for graphics.

http://www.guru3d.com/articles_pages/asus_z170_deluxe_review,5.html

 

[phillyman36]

This is the question i asked Raja from Asus
Raja for the z170 Deluxe the manual says
Pcie slot 3 shares bandwith with sata 5 and sata 6 port
the m.2 slot if set to pcie instead of sata express will disable the sata 1 and sata2 port.

Is there a way to run a intel 750 ssd in the 3rd pcie slot and m.2 ssd(nvme or AHCI) at the same time at full speed right? You would need and x99 mobo for that? What would happen if you had both in?

His answer
The DMI interface between the CPU and PCH is X4 Gen 3. If you use two X4 gen 3 drives on the PCH front end, the transfer speed will be constrained to X4 Gen 3.

Asus suggest putting the pcie ssd in the last slot. Not sure what happens if you were to put the 750 ssd in the second pcie slot.

Just note that if you a m.2 ssd the sata ports on the sata express(sata 1 and sata 2) are disabled.
If you use the last pcie slot it takes bandwidth from either one or both of( sata 5 and sata 6 port)

 

[maddogchen]

Asus suggest putting the pcie ssd in the last slot. Not sure what happens if you were to put the 750 ssd in the second pcie slot.

I think putting anything in the second slot will force the first and second to run at x8 and reduce your video card speed. And thats why they suggest you put it in the last slot.

 

[biostud]

Get the new samsung 950 pro M2 drive instead.

 

[Shmee]

Get the new samsung 950 pro M2 drive instead.

Yes I was going to recommend this, if you can wait.

 

[Chris22963]

Get the new samsung 950 pro M2 drive instead.

Just looking at the articles on that - thanks for the heads up.

I think I'll probably just build using the Intel 750 I already have, and then maybe get a 950 Pro rather than the SM951.

Cheers.