No HDD-Saver for Z170 boards?

It looks like you are right, the Z170 boards I just checked don't seem to have that connector on the board anymore. Plus not listed in the specifications.

Personally, I like that feature, and use it on my ASRock boards that have it. ASRock recently added a stand alone HDD Saver program you can get with APP Shop. So you could use it without starting A-Tuning, or whichever ASRock utility your board has.

I assume a feature like HDD Saver is not "sexy" like fancy audio components on a board, or over clocking and gaming features. So maybe most users don't care much about it.

The way it (must) works may have seemed clumsy to users, the need to restart the PC to detect the drives. That is unavoidable, since power is not supplied to the HDD Saver power port except on a restart, as part of the security concept of this feature.

I don't recall anyone having problems with HDD Saver in the old ASRock forum. I did wonder about the power for two drives being supplied by the board and the small header for the HDD Saver cable. I use it with SSDs, which don't use much power and 99.99% of SSDs only use the 5V rail.

Also, given the complexity of the storage IO features on the Z170 boards, including HDD Saver may have been difficult or impossible to implement too.