Dear Support,
I spent my easter trying to configure Windows 8 on SSD HW RAID-0. Downloaded drivers from Manufacturer, AMD, CD supplied with MoBo. Tried load drivers direcly into installation via DISM. Then I tried Windows 7 with same results. Tried RAID configuration to AHCI and ATA. Tried Full EFI, semi EFI and no EFI (only legacy support). I also tried to format SSDs before install to NTFS. As 1 disk in RAID (via live Linux) and also as both of drives from Windows. Installation on single SSD works well.
My conclusion: Windows is not able to see SSD in RAID, or just this model. Prior to buy I tested W8 install on 2x320GB Hitachi HDD. Worked well. Install even does see bastardy Raid made from SATA 300GB and SATAII 500GB drives. Not able to install tho, but it does see it.
Now I am on Ubuntu since Linux does see RAID with no problems and only Ubuntu was able to install itself without issues except Bootloader, but that was matter of minutes to fix.
I do not think issue is with the drivers since Windows is capable of seeing the HDD drives, but with some compatibility with EVO 850 or SSDs in RAID in general.
My configuration:
MoBo: Gigabyte GA-970A-DS3P (rev. 1.0) BIOS f2j
CPU: AMD FX-4100
Disks: 2xSamsung EVO 850 120GB
RAM: Kingston HyperX Beast 8GB kit 1866MHz