I tried to upgrade the IRST driver from 10.8 to 11.5 on my Asus P8Z68, which resulted in a BSOD at reboot and a shredded C: Partiton.
I use a 20 GB Intel 311SSD as Cache for a Smart Response Technology Set-up with a 500GB WD HDD with Acceleration set to max.
Admitting, I didn't disable the Caching function, before updating the driver.
But before I give it another shot, I wanted to ask if the combination of Z68, Smart Response Technology and Intel Rapid Storage Technology 11.5 is at all compatible ?
At this point the only generic version that we provide for Original Equipment Manufacturer systems is Intel(R) Rapid Storage Technology 10.8.
If Asus* provided you the 11.5 version then they should have already validated this configuration.
I suggest to check directly with your motherboard manufacturer.