Apologies for all of the confusion. You mentioned i7-6900 (without the K) which messed me up.

Yes, the i7-6900K is validated.

T8DC9 Intel Broadwell-E i7-6950X, 3.00GHz to 3.80GHz, 10 cores, 25MB Cache, 140w, three video cards, 06335 thermal pad, N6370 syringe, W2486 Tech Sheet

8WDGP Intel Broadwell-E i7-6900K, 3.00GHz to 4.10GHz, 8 cores, 20MB Cache, 140w, three video cards, 06335 thermal pad, N6370 syringe, W2486 Tech Sheet

KHXMH Intel Broadwell-E i7-6850K, 3.00GHz to 4.00GHz, 6 cores, 15MB Cache, 140w, three video cards, 06335 thermal pad, N6370 syringe, W2486 Tech Sheet

9DNC1 Intel Broadwell-E i7-6800K, 3.00GHz to 3.90GHz, 6 cores, 15MB Cache, 140w, three video cards, 06335 thermal pad, N6370 syringe, W2486 Tech Sheet

PT4MH, CM9N1 Intel Haswell-E i7-5960X, 3.00GHz to 4.00GHz, 8 cores, 20MB Cache, 140w, three video cards, 06335 thermal pad, N6370 syringe, W2486 Tech Sheet

T78NP, 0P7M6 Intel Haswell-E i7-5930K, 3.50GHz to 3.90GHz, 6 cores, 15MB Cache, 140w, three video cards, 06335 thermal pad, N6370 syringe, W2486 Tech Sheet

944F9, D7W00 Intel Haswell-E i7-5820K, 3.30GHz to 3.80GHz, 6 cores, 15MB Cache, 140w, two video cards, 06335 thermal pad, N6370 syringe, W2486 Tech Sheet

From the Area 51-R2 Bios A08 page =

- Supported Intel Core i7-6950X Processor Extreme Edition, i7-6900K Processor, i7-6850K Processor, and i7-6800K Processor.
-Supported 16GB DDR4 Memory

Well... Cant say I'm impressed with the Alienware and how it utilises the 6900k... below is a comparision between the 5930k and the 6900k

so that is quite disappointing for such a substantial upgrade, so I thought I would compare it like for like against another 6900k and set the Asus as a baseline

HOW can there be THAT much of a difference, I understand there could be OC going on with the Asus but still... More worryingly the drop in GPU performance which after the CPU upgrade I thought would give a subtle boost unleasing throughput but the opposite was the case.

Am I being stupid and there is something I'm missing here???

I checked bios and everything seems to be showing ok, under CPU power management config cores 7 and 8 ratio limit is set at 0 compare to 39 for 1&2 and 38 for 3-6. Is that correct?

EDIT: changing ratio to 37 yields results