Assistance needed troubleshooting Z170 Extreme 7+

You have one of the newest SSDs, using the NVMe protocol, did you really expect it to be plug and play?   It is way to early to be blaming the mother board.

Seriously, it isn't plug and play. You are also attempting to use it for the first time as an OS drive, without ever having operated it as just a secondary drive on a PC. You may need to install an OS on another drive and then familiarize yourself with the 750.

What OS are you planning on using? What OS installation media will you be using?

Have you read Intel's installation guide for their PCIe SSDs, and downloaded their NVMe driver that you should (must) install after the OS has been installed. If not, find them here:

https://downloadcenter.intel.com/download/23929/Intel-Solid-State-Drive-Data-Center-Family-for-PCIe-Drivers

Since you can get into the UEFI, you have passed POST with your memory, etc, so what's left is getting your 750 recognized. First you should mount the U.2 adapter board in the M2_1 slot, the top one of the three when the board is mounted in a PC case. The U.2 adapter and cable connections seem simple, so I would not worry about that at this point.

Quiz question: With the U.2 board in the M2_1 slot, which SATA ports will no longer be available for use?

Steps to get your 750 recognized:

Note: It may take several UEFI option setting changes and restarts before the 750 will appear in the UEFI.

In the UEFI, Boot screen, at the very bottom find the CSM option. It is Enabled by default. Click on it to reveal its sub-options.

Find the Launch Storage OpROM Policy option, and set it to UEFI only.

Next go to the Exit screen, select Save and Exit, and go right back into the UEFI.

Go to the Advanced, Storage Configuration screen. You may or may not find the 750 listed yet.

If it is there, great, if not continue in the section below marked with ###.

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Go to the SATA Mode Selection option, and set it to RAID. Yes I know you are not creating a RAID array, just trust me on this. Go to the Exit screen, select Save and Exit, and go right back into the UEFI again.

Back to Storage Configuration again, can you find your 750?

If so, great, if not continue below in the section marked with ***.
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Can you now find three options, one for each M.2 port, M2_1, M2_2, and M2_3?

You are specifically looking for, M2_1 RST PCIe Storage Remapping. Set it to Enabled. Go to the Exit screen, select Save and Exit, and go right back into the UEFI again.

Back to Storage Configuration again, can you find your 750? If not, let us know.
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My questions about your OS and installation media are still important.

Thanks for the offer, I hope I helped you out a bit.

I asked about the OS you will use, since only Win 8 and 10 have a native NVMe driver. You'll still definitely want to install the Intel NVMe driver, since I've read the MSoft driver has write performance issues with the Samsung MVMe version of the SM951.

I wish I had an Intel 750 to play with. I went with the Samsung AHCI SM951... two actually to use in RAID 0.  I had to learn how the Intel IRST driver and ASRock UEFI options work together to get PCIe SSDs in a RAID 0 array. The UEFI settings are identical to those I described to you, when using the SM951 in RAID 0.

Actually, ASRock has done that with seven Intel 750s, three of the version you have (would be my first choice) plus four of the PCIe slot models. See that on this page, about a quarter of the scroll bar up from the very bottom:

http://www.asrock.com/microsite/Intel100/index.html

Did you ever try the System Browser tool in the UEFI to see if that detects your 750?

There is another way to install Win 8 or 10 that goes one step further than simply using the UEFI (really EFI) Option ROM. That method uses the EFI bootloader with a GPT partitioned drive. The main switch to get that result is setting the CSM option to Disabled. There are a few requirements that go along with that, such as a "GOP" compatible video source (Intel integrated video is GOP compatible) and installing Win 8 or 10 from a USB flash drive. If you want to try that I can point you to some guides that will help you.

When you do install Win8 or 10, you will NOT be able to use the DVD with the UEFI Storage OpROM policy enabled. You can simply mount the DVD and send it to a FAT32 formatted USB flash drive, no larger than 32GB in size, on a functioning PC. That will become your installation media. You can even use the USB 3.0 ports with a USB 3.0 flash drive, and experience a five minute Windows installation. You cannot install Windows with that CSM option set to its default, and then change it to the UEFI option later, it won't work.

I also suggest you allow Windows to format the 750 for you during the installation. You'll be using the Custom installation option anyway to load the driver, so all you do is click on New after the driver loading screen returns to the drive selection screen. Do NOT remove the USB flash drive with the driver file on it until the Windows installation is complete.

My Z170 Extreme7+ has been working flawlessly for me since I started using it. If you are just running the board into the UEFI, to shut it down you must press and hold down the power switch on the PC case or the board until the board shuts off. That takes a few seconds and is normal behavior for this and other ASRock boards I use. Or are you doing it that way now?

Good to hear you have the 750 and the board running well for you now.

PCIe storage device recognition in the UEFI can be very unusual with these SSDs. I'm in an even worse state than you are with my RAID 0 array of AHCI SM951s.

The two SSDs are not shown in Storage Configuration or in System Browser, when in a RAID 0 array. I of course have a Boot Manager entry for the RAID array (with a drive identification string included, instead of just "Windows Boot Manager", Thanks ASRock for this small but important update in the UEFI!)

The only thing that will show the RAID array is the Intel IRST utility in the UEFI. That identifies the RAID array and each SSD. We are in new territory with these SSDs and RAID configurations. A few bumps and glitches are to be expected IMO.

I must say you are right about the system shutdown behavior when pressing the power button while in the UEFI... on a system without an OS installation. My board did the same thing you described, restarting after releasing the power button... while I was preparing to install Windows on the RAID 0 array, for the second time (another long story.)

Thanks for the information about the USB 3.1 Front Panel device. I've never tried it since I have zero spare resources to use with it. It sounds like you did not do a UEFI/BIOS clear to solve the issue, it that correct?