The chipset HM76 is capable of SATA 6 speed ARK | Mobile Intel® HM76 Express Chipset (Intel® BD82HM76 PCH);however, depends on the computer BIOS the support for that speed. Try checking if the computer BIOS has some settings to enable SATA 6.0 Gb/s.
Also, make sure you are currently running the Intel® Rapid Storage File name:SetupRST.exe
Allan.