Thank You for the help. While the driver you suggested did not work, I was able to resolve my problem using hints I found on the internet.  I found a copy of Windows 7 Home Premium w/SP1. I was able to load that version in a RAID configuration and it worked just fine. Once the OS was loaded I went to Dell.com to get drivers and utilities. One of them was the Intel RST. My computer now uses the ssd cache to accelerate. It is back to normal.  ps, I did try to load the os straight to the 32 gb ssd. An error appeared stating it was too small, needing 33gb+.  Thank You for your help. I learned a lot from reading the links you provided.
Hi, I am a newbie here so if I make any noob errors please forgive me. I have the XPS 8500 with 32 gb msata drive cache on the mb. Win 7 is the original OS. My HDD died and when I went to replace it I could not get Win7 to install. The only way which finally worked was to switch from RAID to ACHI. The problem is that Intel RST does not seem to work in this configuration. I am not very familiar with Bios settings so I reset to factory on the Bios and started from there. Do I need to do anything else besides changing from ACHI to RAID? Setting stripe? Do I need to have a driver to install during the Windows 7 install? If so, where do I find it? I have been searching the net with no joy. If there are any step-by-step instructions or anyone can walk me through it I would be extremely grateful. Two days on this now...
Install Win 7 in Raid