about the CAS latency is not what you set up in the BIOS

i don't have your board but i use P55A-UD3P and i5-660 and i think this solution below might work for you.

-Load Optimized Defaults in bios, save/exit bios setup and reboot, and then reset bios to your liking.
-or, Set the bios the way you want it, shutdown and restart computer and next time you are in Windows the CPU-tweaker should correctly report you bios's memory timings
if you change memory timings, memory clock speed and/or QPI link multi again try redo the step.