z710m OC Formula PCIe Lane speeds

Hi,

Just to add to Xaltar's answer, on Intel 100 series chipset boards, like a Z170, the M.2 slots use the resources of the Z170 chipset, not the PCIe lanes provided by the CPU.

This is new for Intel, and unique to the Intel 100 series chipset boards. No other Intel based mother boards are like this, including X99 boards. This is true regardless of the mother board manufacture.

All the other Intel based boards use the PCIe (PCIe 3.0 since Ivy Bridge) lanes in the CPU for the M.2 slots.

So for any Z170 board, the M.2 slot(s) will not use any of the CPU's PCIe 3.0 lanes.

Note that if you use an M.2 SSD in a PCIe adapter card that is used in a PCIe 3.0 x16 slot, or an x8 or x4 slot in a Z170 board, then you will be using the PCIe 3.0 lanes provided by the CPU.

PCIe slots have two important parameters, their physical size and their electrical lane allocation.

Keep in mind that all modern Intel processors, except for the HEDT processors, have 16 PCIe 3.0 lanes. The older Sandy Bridge processors have 16 PCIe 2.0 lanes. Those are the only PCIe lanes that are used with the PCIe x16 lanes.

For Intel processors before the Lynnfield generation, the PCIe lanes were provided by the chipset. Those boards vary in the amount of PCIe lanes available.

Given "only" 16 PCIe 3.0 lanes, does it make sense to have all the PCIe 3.0 x16 slots connected to 16 PCIe 3.0 lanes?

The main reason that is not done is cost. Not just the cost of the PCIe 3.0 x16 lane slots, but the cost of connecting those lanes to the CPU. That adds more cost to the mother board, physically and in its design. Include the factor of an MATX board, with less room to work with, and that becomes more difficult.

Sure it would be nice at times to have all the PCIe 3.0 x16 slots be x16 electrically as well as physically. The question becomes is it worth it and do we want to pay for it.