First off, turning off Turbo Boost wont stop the multiplier. In fact you wont be able to overclock with Turbo boost off. Its Intel SpeedStep thats lowering the multiplier. For the most part, you don't need to turn it off as its not affecting performance. Whats happening is it will lower the multiplier depending on the load.
If your CPU is under light load, it will stay at x16. When its needed, it will jump to x45 which will give you the performance needed. I have mine set to on and have yet to see it stay at x16 when gaming.
Also, I noticed your CPU voltage is pretty low for the x16, do you have it set to auto? If so is it stable? I had stability issues when using auto VCORE and had to manually set it. Make sure your system is Prime95 stable for at least 8 hours and Intel Burnin Test for 20 passes using Very High or Maximum memory. If it fails either you have some tweaking to do.