FX 8320 turbo boost not working

What I want:
AMD FX 8320 @ 4GHz / 4.4GHz Turbo.

Problem:
I've increased the multiplier in BIOS to overclock my AMD FX 8320 to 4000mhz and a turbo of 4400mhz;
Running Prime95 shows a stable 4000mhz in CPUZ.

Question:
Why isnt it going up to 4400mhz under heavy load?

Details:
CPU: AMD FX 8320
Motherboard: M5A97 (1605 latest bios)
Graphics: Gigabyte Nvidia 660ti
RAM: 8GB Corsair Vengeance VP (cant remember any other details about my ram)
Cooler: Cooler Master Hyper 212 EVO
Cool n Quiet: OFF
APM Mode: OFF
OS: Windows 7 64bit
*Uninstalled AMD Overdrive to avoid interference with the overclock.

Thank you in advance.

Is Turbo core boost still visible in bios and if so is it enabled? It could be that when you switched to "Manual" overclocking this feature was disabled.

You do realize, don't you that "Turbo boost" is somewhat of a misnomer in that only some of the cores accelerate. It's a power saving, heat limiting technology. Most overclockers disable turbo so that all the cores will speed up to the same level of overclock. Turbo boost can also have a destablizing effect when overclocking and can limit the amount of overclock.

Found an older blog about design of Turbo Core for AMD.

This comes from an AMD blog before the original FX was even released the end of 2011. I have read a number of articles on how AMD Turbo Core (not Boost) works with the FX processors since it is different from the earlier processors that it was released on.

I copied this one paragraph from an AMD blog and written by AMD personel.
http://blogs.amd.com/work/2011/01/31/bulldozer-goes-to-11/
Does AMD Turbo CORE deliver a guaranteed frequency and can you just set the frequency to a higher multiplier? No, that is not how it works. AMD Turbo CORE is continually monitoring the processor power consumption to determine the maximum processor state. For simplicity’s sake, think of it as the opposite of AMD PowerNow! technology. Instead of trying to watch for usage patterns and lower the processor core to try to reduce power consumption, Turbo CORE is watching the power consumption to see how high it can move the clock speed up. The clock speed will vary but not as much as with AMD PowerNow! because it is moving over a different range and responding to different algorithms.

In some respects that blog article explains better than some review sites what and how Turbo Core was conceived. Even though an old article as I said above.

Now we get to Vishera and Turbo Core 2.1 which I believe is one notch above the early FX at Turbo Core 2.0.
FX-8320 Base and Turbo Core Frequency below:
Frequency 3500 MHz
Turbo frequency 4000 MHz

So now we have an FX-8320 at a base frequency of 3.5Ghz and overclock it to 4.0Ghz which was its' original design Turbo Core Frequency. We have now manually overclocked the cpu to the max speed applied by turbo core when it is balancing current drawn against max draw available. Without a lot of what ifs' the current @4.0GHz manually overclocked and is already at the current consumption that Turbo Core is able to deal with and therefore Tubro Core no longer functions generally. Which is a way of saying that manual overclocking most often will disable AMD Turbo Core.