I recommend updating the firmware of the Thermaltake BlackX Duet device plus updating the BIOS of the motherboard.
If issue persists after that I recommend contacting Thermaltake to see if they have compatibility information.
I update the BIOS and Thermaltake don't have firmware upate for the Black X Duet. I find a post for the same issue but not the same enclosure. http://communities.intel.com/thread/19687?wapkw=port+multiplier See answer from Jose_Intel at the botom.
On the Thermaltake web site : http://www.thermaltakeusa.com/Product.aspx?C=1346&ID=1895#Tab5