That type of issue has been reported before and it has been addressed correcting the configuration settings on the operating system, this is not caused by Intel(R) Rapid Storage Technology.
You may refer to this thread as a reference for the troubleshooting you can follow:
http://communities.intel.com/thread/12381
Some others have reported that if you need to check the "Turn off Windows write-cache buffer flushing on the device" option on Policies tab in the RAID volume properties (Disk Management> Computer Management > Device Manager > Disk Drives.
Also check on policies to see that "Enable write caching on the disk" is checked and that "Enable advanced performance" is also checked.
Keep in mind that when using that type of cache, an UPS should be used and that the operating system may disable this cache feature, if an UPS is not present, which switches back to write-through