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M.2 PCIe SSD - will it "disable" a SATA port or "share bandwidth"?

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Topic

baldy95307 1 month ago

Just a little nagging question. According to the mobo manual for the Gigabyte B360-HD3, a M.2 SATA SSD device will "share bandwidth" with certain SATA ports. Specifically it says " The M2A_32G connector shares bandwidth with the SATA3 5 connector; the M2P_16G connector shares bandwidth with the SATA3 1 connector.

PCPartPicker adds the following "The motherboard M.2 slot #1 shares bandwidth with a SATA 6.0 Gb/s port. When the M.2 slot is populated, one SATA 6.0 Gb/s port is disabled. The motherboard M.2 slot #3 shares bandwidth with a SATA 6.0 Gb/s port. When the M.2 slot is populated, one SATA 6.0 Gb/s port is disabled.

My question centers around PCPartPicker's use of the word "disabled". I can understand it if an M.2 SATA SSD is installed, but does a M.2 PCIe SSD actually disable the corresponding SATA port?

Comments Sorted by:

Gilroar 1 Build 1 point 1 month ago

My question centers around PCPartPicker's use of the word "disabled". I can understand it if an M.2 SATA SSD is installed, but does a M.2 PCIe SSD actually disable the corresponding SATA port?

Yes. Most chipsets do not have enough PCIe lanes to fully enable the motherboards feature set as most users will never fully utilize those features. So when they need four PCIe lanes for a M.2 they disable part of a Sata controller since you are adding a drive in its place.

Intel may do this with any M.2 depending on the number of Sata the board supports.

AMD depending on how they choose to use the lanes may or may not on the main M.2, and if there is a second M.2 always do it. On AMD the second M.2 is generally also wired to the 2.0 standards not 3.0 or they disable most of the motherboards slots to pull enough 3.0 lanes.

You also have to watch on both as many boards to cut costs only wire a single M.2 to support Sata.

baldy95307 submitter 1 point 1 month ago

Thanks for those comments. I guess one should follow the mobo manual's section which advises exactly which SATA ports are disabled and then make sure not to plug in any SATA devices on those ports.

In the case of the Gigabyte B360-HD3, those disabled ports would be SATA #1 and SATA #5.

Gilroar 1 Build 1 point 1 month ago

The others should be fine to use just avoid those two.