I noticed that too on a Tyan motherboard I had briefly, I was able to squeeze 3000 mhz per core after adjusting some BIOS settings but wasn't seeing the full turbo per core. Them turbo ratio limits, doe, :/I have to say that I'm very impressed at his much Intel has managed to lock down these CPUs! I hadn't quite realized just how much and since they were so cheap I figured that I'd buy another and run it in an X79 SP system and at least get a little boost over stock...
So far from what I can tell I'm getting exactly...nothing.
Per-core turbo limits are in full effect, as is the TDP limit (AFAIK, it's not getting hot enough to throttle). mprime running 16 threads with an AVX FFT pegs all the cores at base 2.6GHz. Running the older core2 FFT will get them up to the `7-8 core' turbo limit of 3.0GHz. It really does seem that server boards are the way to go, since it doesn't seem like there's much you can do other than stock with these.