This is on my home office Z600 that is the one I've been experimenting with using the Kingston Predator 240GB M.2 AHCI based controller PCIe SSD on. HP has 2 Intel storage controller installers out currently for the Z600, one 9.x and the later one 11.x. I discovered that I needed to use the 9.x one for the Predator to work, and it would instant blue screen with the 11.x. I got a 500GB SSD for my documents drive you can see in the pics below. All that is rock solid.
I added in a spare 3TB drive I have, shown. This is a HP 638516-002 SATA2 Hitachi MB300EBUCH drive I got brand new off eBay a few years back, and it was a server drive which would not be recognized by W7Pro64 until I did my usual DBAN low level reformat (which took several days). This process cleared whatever was on the boot sectors preventing it from being usable on my workstation, and I then took the now-raw drive, created a single GPT partition, and did a standard long type NTFS format of it (all settings at default).
Remember that there can be some issues with non-HP SATA3 drives when being run in HP SATA2 workstations (which the xw and ZX00 generation of workstations are). That is why I wanted to use this HP SATA2 drive for experimenting with.... to take that variable out of the mix. HP firmware on SATA3 HDD drives and (and I believe also SATA3 SSD drives) has been stated by HP to resolve this issue when using them in SATA2 workstations. This all is discussed elsewhere in the forum, including recently.
So, Dan_WGBU was right once again. I don't need a 3TB documents drive in this workstation, and the combination of a SSD for my documents drive plus the M.2 PCIe SSD as my boot/applications drive has made this Z600 (2 x X5675) a very snappy workstation indeed. Here are some pictures of the 3TB in Device Manager and Disk Management. I have no idea why sometimes these pics show up so small. If anyone has tips to fix that please let me know:
