MP 1,1-5,1 Mac Pro 5.1 Only Spooling Up 3 of 4 Internal Drives.

[fotobratt]

I have a 5.1 Mac Pro tower...running 10.13.6 on an SSD out of my broken Imac and 10.14x on a 2 TB PCI drive, Radeon RX 580 8g, internal drives are the 512 apple ssd, 2tb crucial, 2tb 7200rpm and a 6tb 7200rpm....it will only boot 3 of the 4 drives in trays...and it does this in both operating systems....and it seems random on which will get booted. I've moved them around and done restarts, one of the two bigger Non SSD drives constantly won't spool up. It's not the ports as each one will work, but only 3 at a time. Not sure what to look at or do as a work around.

 

[h9826790]

The newer HDD has pin3 compatibility issue on the cMP.

In SATA 3.3 standard, pin 3 is to control the Power Disable function (PWDIS). On cMP, the SATA 2 port may erronously power the pin 3 during boot (warm restart usually has more trouble on this matter), then the HDD will be disappeared inisde macOS.

For some drive, this can be work arounded by putting a small tap on the HDD's pin 3.

https://forums.macrumors.com/threads/macpro-5-1-high-capacity-hard-drives.1971809/page-2?post=25660950#post-25660950

 

[fotobratt]

hard to tell from that photo, but is it JUST the 3 pin covered in tape or the first 3?
Also...update...it seems if I pull the PCI flash drive, the 4 internal drives spool up just fine.

 

[h9826790]

hard to tell from that photo, but is it JUST the 3 pin covered in tape or the first 3?
Also...update...it seems if I pull the PCI flash drive, the 4 internal drives spool up just fine.

Just pin 3.

Yes, AFAIK, any small changes may make the difference (either software or hardware). I don't know the actual reason, but may be it change the HDD spin up timing a bit, which eventually cause the difference.