Pro Gaming Z170 - does the m.2 slot use PCIE channels for NVMe speeds?

[THX1139]

The manual says that the m.2 slot disables SATA 1 so does that mean the m.2 slot is only good for SATA m.2 drives and not NVMe m.2 drives that use PCIE lanes?

[Nate152]

The Z170 pro gaming has 20 pcie lanes, 16 from the cpu and 4 from the chipset.

You can use pretty much any M.2 NVMe drive which uses the 4 pcie chipset lanes.

[THX1139]

It's still not clear how my PCIE lanes are being distributed right now though. Is there some way to find out? Currently I have 21 lanes worth of hardware in place so it would be interesting to know what is not getting a full allocation.

Is it possible to make one of the GTX 970s use only 4 PCIE lanes? It is only there to mine cryptocurrency. The other 970 I want to be able to use for gaming and video editing though. I will try to put off upgrading for at least another year.

[THX1139]

Thanks for responding. What if the PCIE slots are populated with two GTX 970s, one PCIE x4 to m.2 slot adapter and one PCIE x1 to 4x SATA adapter? If each 970 uses eight lanes, the m.2 adapter uses four and the SATA adapter uses one then that's already 21 lanes giving me minus one lane! If I add an m.2 drive to the m.2 slot then that's minus five! I wish there was some insight into how my lanes are being distributed. Where do the four from the chipset go?

[Nate152]

Two 970's = 16 lanes from the cpu.

That leaves 4 lanes from the chipset for an M.2 drive which = 20 lanes, after that you'll have to make sacrifices.

z270 has 24 lanes, 16 from the cpu and 8 from the chipset, or the Rampage boards support 28 lane and 40 lane cpu's.

[xeromist]

Even if you could reduce one of the slots to x4 you would not be able to use it for the other GPU. There's no such thing as PCIE x12. But I wouldn't worry about a 970 on x8. From everything I've seen it basically makes no difference in performance.

[THX1139]

xeromist wrote:
Even if you could reduce one of the slots to x4 you would not be able to use it for the other GPU. There's no such thing as PCIE x12. But I wouldn't worry about a 970 on x8. From everything I've seen it basically makes no difference in performance.

I'm not interested in using the other four PCI-E lanes on the first 970. I want to use them for an NVMe SSD.


The only option appears to be to reduce all the PCI-E sockets to Gen1 or Gen2. I don't know whether that affects the PCI-E lanes assigned. If so, it would have been much more useful to be able to control these independently.

[xeromist]

Ah, I misunderstood since you mentioned the other GPU. Basically x16 goes to your slots 1 & 2. If you have one card installed it gets x16. If you have two installed they each get x8.

Everything else (all other slots, SATA, USB, & the m.2) go through the chipset.

Setting PCIE 2.0 mode isn't going to change how those lanes are divided, just force compatibility if necessary.

One option would be to use an x16 to x4 or x1 ribbon adapter and connect the extra 970 to one of the other slots. Then you could use the 2nd x16 slot for an NVMe adapter card. Your first GPU would get x8 and your NVMe adapter would get x8. Your other GPU would be forced through the chipset.