STRIX Z270E M.2 SSD + pascal GPU and potential SLI bottleneck

[Redrum333]

Hello guys,

I have a small question for the community as I'm planning to finish off my new computer config. I would love to have an M.2 SSD drive, along with a new pascal gen. GPU and perhaps another one in SLI configuration (in future) on ROG STRIX Z270E motherboard. Is there any chance that M.2 drive working in PCIe configuration will bottleneck the performance of one/two graphic cards? If ther eis such chance, I'll just stick to a SATA SSD drive. (I've already seen topic on this problem, just wanna clarify that for my case). The processor is I5-7600K.

Cheers!

 

[raisonjohn]

No chance. In your planned setup, you have a grand total of 40x PCIe3.0 lanes: the CPU (i5-7600K) controls a maximum of 16x PCIe3.0 lanes (used for your graphics card/s); while the PCH (Z270 Chipset) controls up to 24x PCIe3.0 lanes (which includes the M.2 slots).

In the Asus Strix Z270E motherboard, the PCIe lanes controlled by the CPU are:
- The first x16 expansion slot (PCIE_X16/X8_1) running at either [x16] (for a single GPU) *or* [x8] in conjunction with another GPU
- The second x16 expansion slot (PCIE_X8_2) running at [x8] (for a dual GPU setup in conjunction with the first expansion slot)
TOTAL: 16x (either at [x16] or [x8/x8] setup)

The PCIe lanes controlled by the PCH are:
- The third x16 expansion slot (PCIE_X4_1) running at [x4] (for a 3-way CrossFire setup in conjunction with the other x16 slots)
- The first x1 expansion slot (PCIE_X1_1) running at [x1]
- The second x1 expansion slot (PCIE_X1_2) running at [x1] (Shared with front USB3.1 port)
- The third x1 expansion slot (PCIE_X1_3) running at [x1]
- The fourth x1 expansion slot (PCIE_X1_4) running at [x1] (Shared with front USB3.1 port)
- The rear USB3.1 port (1A1C/BACK) running at [x2]
- The Wi-Fi module running at [x1]
- The LAN module (Intel_I219V) running at [x1]
- The DMI3.0 Link between PCH and CPU running at [x4]
- The first M.2 socket (M.2_1), if configured in PCIe mode, running at [x4] (Shared with SATA_1 port if running in SATA mode)
- The second M.2 socket (M.2_2) running at [x4] (Shared with SATA_56 ports)
TOTAL: 24x

So, if you have a GPU in SLI connected to the (PCIE_X16/X8_1) slot and (PCIE_X8_2) slot, then both GPU's will run in [x8/x8] controlled by your i5-7600K. If you add M.2 SSD's, populating both (M.2_1) socket and (M.2_2) socket, and both in PCIe-mode, then both M.2 SSD's will run in [x4] controlled by your Z270 Chipset.

 

[Redrum333]

Thanks for the elaborate answer, problem solved 😉

 

[Dogbites]

No chance. In your planned setup, you have a grand total of 40x PCIe3.0 lanes: the CPU (i5-7600K) controls a maximum of 16x PCIe3.0 lanes (used for your graphics card/s); while the PCH (Z270 Chipset) controls up to 24x PCIe3.0 lanes (which includes the M.2 slots).

In the Asus Strix Z270E motherboard, the PCIe lanes controlled by the CPU are:
- The first x16 expansion slot (PCIE_X16/X8_1) running at either [x16] (for a single GPU) *or* [x8] in conjunction with another GPU
- The second x16 expansion slot (PCIE_X8_2) running at [x8] (for a dual GPU setup in conjunction with the first expansion slot)
TOTAL: 16x (either at [x16] or [x8/x8] setup)

The PCIe lanes controlled by the PCH are:
- The third x16 expansion slot (PCIE_X4_1) running at [x4] (for a 3-way CrossFire setup in conjunction with the other x16 slots)
- The first x1 expansion slot (PCIE_X1_1) running at [x1]
- The second x1 expansion slot (PCIE_X1_2) running at [x1] (Shared with front USB3.1 port)
- The third x1 expansion slot (PCIE_X1_3) running at [x1]
- The fourth x1 expansion slot (PCIE_X1_4) running at [x1] (Shared with front USB3.1 port)
- The rear USB3.1 port (1A1C/BACK) running at [x2]
- The Wi-Fi module running at [x1]
- The LAN module (Intel_I219V) running at [x1]
- The DMI3.0 Link between PCH and CPU running at [x4]
- The first M.2 socket (M.2_1), if configured in PCIe mode, running at [x4] (Shared with SATA_1 port if running in SATA mode)
- The second M.2 socket (M.2_2) running at [x4] (Shared with SATA_56 ports)
TOTAL: 24x

So, if you have a GPU in SLI connected to the (PCIE_X16/X8_1) slot and (PCIE_X8_2) slot, then both GPU's will run in [x8/x8] controlled by your i5-7600K. If you add M.2 SSD's, populating both (M.2_1) socket and (M.2_2) socket, and both in PCIe-mode, then both M.2 SSD's will run in [x4] controlled by your Z270 Chipset.

 

[Dogbites]

So to be clear, there is no bottleneck? I have been looking for info on this subject that doesn't make my head explode. I currently have the 6700 cpu, Asus Z279e with 1 M.2 2280 NVMe, 2 gtx 970's. I would like to add a second M.2 2280 NVMe but I too am afraid of a issue.