> Ten rašo: 1 x M.2 Socket 3, , with M Key, type 2260/2280 storage devices support (PCIE mode)

https://www.asus.com/us/Motherboards/Z97A/overview/

Speed up your system with M.2
With two native PCI Express 2.0 bandwidth, M.2 supports up to 10Gbit/s data-transfer speeds.
It is the perfect choice for an operating system drive, making your whole PC work that much faster.
It supports Intel® Rapid Storage Technology to ensure even faster access to data,
refresh applications automatically and awake from sleep in just seconds!*

> Tai Z97 tas PCIE mode yra PCIe 1.0, o Z170 PCIe 2.0? Taip aš supratau?

Ne, Z97 tas PCIE yra 2.0 .. o Z170 PCIe yra 3.0.

https://en.wikipedia.org/wiki/LGA_1150#Second_generation
Z97 - Chipset-attached PCI Express - 8 × PCIe 2.0 ×1

https://en.wikipedia.org/wiki/LGA_1151#Skylake_chipsets_.28100_series.29
Z170 - PCH PCI Express configuration - 20 × 3.0

zr - http://assets.hardwarezone.com/img/2015/10/z170-chipset-block-diagram.jpg