M.2 2280 Gen4 PCIe x4 NVMe 3D TLC Internal Solid State Drive (SSD)

For now only usable on x570 Ryzen platform but I heard some rumors about Asus releasing a BIOS for x470 to be compatible but only on PCIe bus controlled by CPU as other PCIe lines are controlled by chipset and x470 doesn't have that in it. That's another reason x570 chipset is fitted with an active cooler.
Intel users will have to wait a year or two.

SIW2 said:

I suspect the B75 mobo won't support gen4. Gen3 prices likely to drop, which is good news.

They will still work with gen 3 boards but at reduced speeds, either CPU or chipset have to be PCIe 4 compatible to work full speed.

Techymike said:

It seams that the bottle neck would still be limited by the buss?

Yes but PCIe 5 is in the works. Every new version doubles the bandwidth of preceding one. Memory chips themselves are still faster than controllers and buses.

Techymike said:

As the X470 MB has the M2 slot I will be installing the Samsung 970 EVO Plus Gen 3 with 1TB. It will allow the max use out of the MB.

There's another M.2 slot (the lower one) but it's x2, SATA mode.

Strictly FYI -

I feel that PCI NVMe is where it's at!

Take a look at this, too...

Toshiba Introduces New Tiny NVMe SSD Form Factor

Cool!