Replace the HDD with an SSD. During boot, the RST bios screen comes up. I can exit and the system appears to run nominally. It seems the system wants some kind of configuration information. How should I configure RST with the HDD replaced with an SSD?
You don't need it -- and in fact running a cache mSATA with a native SSD may actually wind up slowing the system down. If you've installed the OS to a hard drive, just remove the cache drive altogether.
Alternatively, if you are not using the msata drive, then you could change the sata operation in BIOS from Intel Rapid Storage to AHCI. The IRST screen on startup will not come up then. However, changing the boot operation, might cause the system not to boot into Windows. You would then need to reinstall the OS.
Using the msata with the SDD is not recommended as advised by ejn63.
Also, please click my DELL-username and write me a private conversation with the service tag and your contact details(Name and Email) for case records.
Let us know if you have any other queries.
Change your SATA operation to AHCI and remove the mSATA SSD it is obsolete. See here for more details: