M2D_32G M.2 connector on Gigabyte GA-Z170X-GAMING 7

[Touz]

Hello,

I've been reading the manual of the Gigabyte GA-Z170X-GAMING 7. There is two M.2 port, one shared with the PCieX4 lane and the other who use the Intel® Z170 Express Chipset with SATA3 and Express ports.

The question concern the M2D_32G M.2 port which use the Intel Chipset. If you connect an M.2 PCie X2 SSD in that slot, it disable the SATA3_2, SATA3_3 and the second SATA Express port.

If you connect an M.2 PCie X4 SSD in that slot, it disable the SATA3_0, SATA3_1, SATA3_2, SATA3_3 and the second SATA Express port.

Considering it disable 2 additionals SATA3 port, I would expect it to run at X4 speed, but in the manual it says that the M.2 PCie X4 SSD will be throttled down to X2 speed if connected in that port.

The question is : Why does it need to disable 2 extras SATA3 port if it's going to run the same speed as an M.2 PCie X2 SSD that doesn't have to have those ports disabled?

Thank you !

[Touz]

I can't find how to modify my first post, but I would like to add a correction, it is my understanding after doing a little more research that the third PCieX4 slot is also controlled by the Intel® Z170 Express Chipset.

But now I have more question.. Using the third PCie slot or the M.2 M2H_32G port would hold down 4 PCie lanes. Then using the M.2 port M2D_32G would disable 2 SATA3 and 1 SATA Express.

Now what happens, if I decide to use the last 3 remaining PCie X1 slot? Is there 3 PCie lanes reserved for them, if they are shared with the SATA3 and Express, which one will be disabled?