This has been driving me bonkers! I have RTFM everything I can find and this should be working fine. My config:

Asus Z97-a motherboard (Series 9 chipset) BIOS 2205
Rapid Storage Technology Firmware 13.0.0.2075
RST Driver and Software 13.6.0.1002
RAID mode
Intel i7 4790k processor 4 GHz (not overclocked)
32 GB RAM
2 x 4 TB Seagate SSHD (hybrid) drives (ST4000DX001) in RAID1 configuration
Plextor M6e Series 128GB M.2 PCIe Internal Solid State Drive (PX-G128M6e) Latest 1.0.5 firmware
Windows 7 Ultimate 64 bit

I can see the SSD during installation of the OS (i.e. I could have loaded the OS onto the SSD).

I set up RAID1 via Cntrl-I before installing OS. For Windows 7 to see the 4TB RAID1 array, I had to load the 64 bit F6 drivers at the screen where you can select the drive to install on and partition the drives. I partitioned the RAID array drive via F10 and DISKPART in GPT format with 256MB EFI, 256MB MSR, then remainder of disk space as the primary OS partition.

I carefully loaded Windows 7 and all updates. Made sure .NET was installed and updated.
Loaded Intel Chipset Installation Utility and MEI before loading the RST application.
Loaded RST application. Saw that the array initialize had started. Let that finish.
Loaded RST application.
Open RST application and no sight of the SSD drive. ?! And no Acceleration options. Anywhere...
In RST app I can see array and two 4 TB drives as well as both DVD drives. No SSD drive.
Computer is running fine and Device Manager is "greened" up. All drivers are loaded and all devices showing normal. (I am typing this on the same computer).

After reading the RST Help information, I see that the RST application should show the SSHD (hybrid) drives as green drives vs blue. They are showing as "blue" plain SATA drives. Aha!
(see below for screen captures)

From what I read, I should get the accelerate tab or something regarding the SRT hinting to the hybrid drives... Everything I see is like I have two standard drives.

I'm at a loss. I did read where someone shrunk their drive partition slightly to make room at the end. May give that a try.

What should I check?!!! Thanks!

Ok. I think you're on to something. I'm excited now. :)

First off, I see the difference in the Device Manager Window that you have 4 Standard ACHI - Controllers (albeit auf Deutsch). ;> Ich spreche ein klein wenig deutsch. :)

I have one Standard ACHI - Controller plus an ATA Channel 0 controller device.

My entry for Standard ACHI - Controller -> Hardware Ids is almost identical

See screen shots below:

Ok. I might be missing what you are telling to do. :) What should I do now? :) Or am I at an impasse?

Also, the SSHD drives are not recognized as hybrid drives (at least what the disk state key shows). RST is supposed to give hints to the SSHD drives of what to cache.

From what it appears, the acceleration portion of RST is not working.

Thanks for being responsive!

I've already loaded the OS twice. My wife is starting to get annoyed with the computer on the dining table. ;>
Just to be clear: I have the OS booting off of the RAID1 array of 2 x 4TB Seagate drives. My only desired use of the Plextor M6E PCIe M.2 SSD drive is to use it as Smart Response Technology cache. I am *not* booting off of the SSD.

Does your Samsung SSD show up as SATA and is listed in RST? I'm beginning to think that I may have to punt trying the Plextor. I've certainly burnt more than $120 of my time trying to make it work doing every permutation of combinations that I can try (various UEFI settings, PCIe NAND configuration, reinstalling RST application, disabling the ATA Channel O controller driver, etc., etc).

I was reading the "No RST support for PCIe storage devices, when the SATA controller is configured for AHCI mode" as just meaning the motherboard BIOS has to be in RAID mode, but you have opened my eyes to see that the Plextor SSD has it's own controller built in and it is operating in *ACHI* mode...

I'm about ready to bail on using the M.2 port and just get a good 6 Gbps SATA drive to use for caching until the RST driver works better.

Getting too old to beat my head against the wall. I punted on the Plextor and bought a Samsung 850 Pro 128GB 2.5-Inch SATA III Internal SSD. RST saw it right away and had the accelerate option.

Still have the Plextor drive. I'm using that for my swap file since it has the fastest connection (2 x PCIe 2.0).

Thanks for the assistance!