M14x R1, Unable to select Disks when creating RAID 0

@Kevin K  A RAID setup that involves using one of the disks as a cache isn't "traditional" RAID, so even if it showed up as a RAID 0 in the boot-time Rapid Storage interface after it had already been set up, you might not be able to set it up in that interface again.  The normal way to set up a cache disk is to initially install Windows directly onto your main disk, in your case the large 698.6 GB disk, then install the Rapid Storage application, and enable the cache using that application within Windows.  Dell has a guide for this purpose here.

Hi @Kevin K  welcome to this user to user discussion forum. This is not Dell Support. 

Dell Support for (2013) Alienware M14x Documentation says motherboard is designed for SATA HDD. Dell Drivers & Downloads support the Windows 7 x64 operating system. 

Advocate get USB external enclosure for SATA M.2 2280 card. Use Macrium Reflect Free to clone HDD OS(C:) boot drive to Single 1TB M.2 2280 SATA SSD card. Then replace HDD with Dual-Slot M.2 Drive to SATA Adapter for 2.5inch Drive Bay. Alienware M17x R1 performance will improve. 

The Alienware M14x enclosure depth should accommodate caddy for two adapter trays. The open tray adapter allows a good air flow to keep the M.2 2280 drives cool. The second M.2 2280 slot can be used for data storage. 

Installing Windows 10 x64 and updates should be contemplated. Look for similar Alienware CPU & GPU model that can read across. Perhaps other users have already undertaken upgrade and have identified where to get Windows 10 x64 Dell support.

Dual-Slot M.2 Drive to SATA Adapter for 2.5inch Drive Bay 

Please click on Kudos to say thank you for response from user that is not employed by Dell. Please share an update on progress, so that other users derive benefit from your experience. Thank you. 

If your M14x has the mSata SSD then you have the R2. The R1 did not have an mSata port.

If you'd like to re-enable the mSata as a cache drive then you need to make sure the BIOS is set to RAID and then you need to install the Intel RST driver and user interface. Once you've done this then you open the RST program and there should be an option to Enable Acceleration. 

If you don't see an option to Enable Acceleration then you may have to go to Disk Management and format the mSata SSD and make it Unallocated. 

This version should work

https://downloadcenter.intel.com/download/28992/Intel-Rapid-Storage-Technology-Intel-RST-User-Interface-and-Driver

A dedicated 2.5" sata SSD is a better option though and you will find that performance is greatly increased over the cache setup. 

Please let @jphughan , @crimsom , @mattyb3  Know if any solutions worked for you and please click Kudo for their posts if they were helpful. Also Thats a nice laptop aswell.

I've only just looked at the photos properly. By the shape of the display assembly, you have the Alienware 14 (not the M14x R1 or R2). This doesn't change the process to set up drive acceleration. 

HI @Kevin K  Please look on base cover for private Service Tag and insert this into Product Support so that Dell can identify your laptop Model and Revision number. Do not share your private Service Tag or Express Service Code in this public forum. Thank you.