2 NVMe M.2. PCIe 3.0 x4 ssd on Z370

[kens30]

Hi to everyone.
I want to add another NVMe M.2. PCIe 3.0 x4 to my pc and was wondering if they will both run at PCIe 3.0 x4.
I understand that the Z370 chipset has 24 lanes and bios has the option to set both at PCIe 3.0 x4 while disabling 2 sata 6g ports.
So the main question is will both nvme ssd's run at at PCIe 3.0 x4 and GPU run at PCi 3.0 x16 with the above config?
Thanks.:)

[ben7272]

They will both run at x4 but you need to configure them as such in the BIOS. The socket designated 2_1 can be set to [Auto] [SATA] or [PCIe], I suggest setting this to [PCIe]. The setting is in the Advanced Menu under the Onboard Devices Configuration. The socket designated 2_2 is configugred differently, the setting here is whether you use X2 or X4 speed. Setting to [X4] speed disables SATA5 and SATA6 sockets on the motherboard so make sure you are not trying to use them.

I have two NVMe PCIe 3.0 X4 devices configured as suggested above and both are confirmed to be operating at X4 speed using the Samsung NVMe utility. None of this impacts your PCIe X16 slot

[kens30]

ben7272 wrote:
They will both run at x4 but you need to configure them as such in the BIOS. The socket designated 2_1 can be set to [Auto] [SATA] or [PCIe], I suggest setting this to [PCIe]. The setting is in the Advanced Menu under the Onboard Devices Configuration. The socket designated 2_2 is configugred differently, the setting here is whether you use X2 or X4 speed. Setting to [X4] speed disables SATA5 and SATA6 sockets on the motherboard so make sure you are not trying to use them.

I have two NVMe PCIe 3.0 X4 devices configured as suggested above and both are confirmed to be operating at X4 speed using the Samsung NVMe utility. None of this impacts your PCIe X16 slot

Thanks a lot for confirming the above config works:)
Now time to order a Samsung Evo plus nvme 1tb....Hmm or maybe a Pro as originally planned..

[Ch3vr0n]

You shouldn't need to change the AUTO one, that's why it's AUTO. It'll AUTO detect PCI-e and behave as such. Can't speak for the other one. That depends on the exact motherboard, you can't just make a blank statement like you're doing and say "change this to that". The setting you're talking about may not even be there.

[kens30]

Ch3vr0n wrote:
You shouldn't need to change the AUTO one, that's why it's AUTO. It'll AUTO detect PCI-e and behave as such. Can't speak for the other one. That depends on the exact motherboard, you can't just make a blank statement like you're doing and say "change this to that". The setting you're talking about may not even be there.

Thanks for your concern Ch3vr0n,
i agree on you about generally anyone on this forum making statements like "change this to that" without knowing or being sure,
although ben7272 is spot on on his reply.
The bios options are there and my specs are listed so he might have a similar mobo or checked the user manual for my Code X.

[Ch3vr0n]

Well from your manual. Page 3-18

M2_1 Configuration: AUTO/SATA/PCIE Mode

Auto: auto-detects M.2 device mode if SATA device is detected, SATA6G_1 will be disabled.

That's the default setting and you don't need to touch that. If it detects a PCI-E device, it'll work just fine and no sata ports will be disabled, if it detects a sata device SATA6G_1 will be disabled. The other 2 options explicitely configure the slot for the proper protocol (shouldn't need to do that.)

Page 3-19

M.2_2 PCIe bandwith configuration: X2/X4

X2 mode: Run at x2 mode with SATA6G_56 Enabled (they probably mean ports 5 and 6 here)
X4 mode: Run at X4 mode for higher performance with SATA6G_56 disabled <== enable that option and you'll lose 2 sata ports

So in your case, pcie device in slot one, doesn't change a damn thing IO wise. PCIe device in slot 2, you have a choice. Half performance and ALL sata slot's or full performance and go down from 6 slots to 4. Probably because it cuts into the CPU lanes or PCH lanes, i'm not fully known with which it would be.