I don't exactly agree that it's slower to move to IVB.
At 4.6 GHz, my 3770K pulls ~75W. My 3820 drew more than that at stock. My first 3960X...oh boy. 155W at stock.
For up to two GPUs, IVB seems to perform better, to me, especially if you get a board with the PLX PEX8747 chip that actually uses the chip the right way, like the Gigabyte Z77X-UP7.
When comparing the i7 3820, i7 2600K, and i7 3770K, the 3770K wins, every time, in my books.
Yes, he'll lose two cores...so unless you actually have something that uses those cores...there's nothing to be lost, performance-wise. Probably 95% of people do not use the full potential of their CPU.
NOw, if you're a cruncher, sure, X79 is best, or is you run 3-4 cards, but two or less...I find it hard to ignore IVB, in such a way that my 3960x that can do 5 GHz on air...sits on my part shelf.
Personally, I think my perspective here is different because I actively use all the current platforms. Not many do.
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