Your numbers are wront AC.
Well I don't know where you have those numbers from. I would say that top bin Nehalem-EX will be 10-15% slower than lowest bin (3.0GHz POWER7). But this is chip performance (specint), not system performance like for example a TPC-C, SAP 2/3 Tier.
If you look at Westmere versus Nehalem -EP then Intel had to raise the clock 13% to almost keep up with Nehalem-EP on the per core level. On a benchmark like specint_rate then the per core per GHz of Nehalem- EP is 19% faster compared to Westmere. Nehalem-EX won't be
You can see the same effect if you compare 4 core/chip POWER7 to 8core/chip POWER7. There is nothing surprising in this.
And I can only conclude that you don't really know what you are talking about, when it comes to price. You can't really buy a POWER7 chip, only the server.
So with regards to tin price. Then a current x3850 M2 with 4P and 128 GB ram costs around 40KUSD, a Nehalem-EX machine would most likely cost a little more.
A power 750 with 4P@3.0 GHz and 128 GB RAM costs 100KUSD.
But you also have to remember that the power 750 will be faster than a x3850.
If you factor this in, then I think that a factor of of 2 when it comes to price performance in specint kind of workload.
Currently the power 750 is way more than 2.5 times faster than current x3850. The current x3850 does 684,508 tpmc. We don't have any numbers for the power 750. But the old firstname.lastname@example.orgGHz power6 power 570 does 1,616,162 tpmc with a rperf rating of 134.35. Now a 32 core power 750 has a rPerf rating of 292.47. Now I won't say that the power 750 will do 3.5M tpmc.
But if you compare current POWER7 to x86 gear using dunnington, I know where the price performance benefit is...
Sure a x3850 using Nehalem-EX would most likely do something between 1.5M-2M TPM-C.
So your 10x in price is.. well.. more likely somewhere in the factor of 1-2.