MohammedSF wroteit's not only the tri-gate transistors what made IB's hotter than SB's..
In IB's, intel uses a shitty thermal compound "TIM" to transfer heat between CPU die and it's IHS, it's an unexplained step from intel because they always use a method called "Fluxless Soldering" to attach the IHS for maximum heat transfer (as we know, transferring heat from metal-to-metal is extremely faster than metal-to-TIM-to-metal again)
In SB's intel used the Fluxless Soldering method while all IB's use TIM method, not only that, intel used extremely low quality ones, add tri-gate transistors to that combination and you'll get an oven under the hood !
Lots of mods are out there removing the IHS from the IB's and replacing the TIM with higher quality ones, a minimum of -10c on core #1 and 4~5c less on other cores, replacing the TIM with high-expensive diamond powder TIM that contains metal will fuse the surfaces between the die and the IHS and make it as cool as SB's and clock much higher..
Why intel used that method ? Marketing !
simply because a Fluxless-Soldered 3770k will eat their +1000$ extreme cpu's for launch !
They want us to be confused in our choice, should i get SB and clock it +5GHz ? or get an oven with PCIE 3.0 support ? or should i buy a 1000$ cpu ??
Think and make your choice..
Edit: I've made mine, a 2700k is the best choice for me, 5GHz means it's equal to a 3770k @ 4.6GHz, 5.2GHz SB = 4.8GHz IB and it's easy for SB to OC with a decent cooling while it's hard for an IB..
PCIE 3.0 ? who cares, even a GTX680 cant fully utilize 16x PCIE 2.0 !
I'm not sure i agree with your reasoning here.
Concerning ivy's thermal issues, it might very well be a cost cutting measure rather than a marketing trick from intel to put in the underperforming thermal compound on Ivy.
Even if ivy could be clocked extremely high, it simply cannot match their 6-core extreme range in highly threaded applications, whose users are the ones targeted by SB-E. The cpus operate in different markets and are intended for different users. There's not that much cannibalism going on between intel products.
And regarding your choice of cpu, i'd have said go Ivy definitely. Being future proof with pci3 , native usb 3.0, better integrated gpu (great for quicksync) etc..surely beats a small overclocking advantage?
And even then, as you mentioned with ivy at 4.6, you have to get SB above 5 Ghz for any added benefit, not that easy even for Sandy. how that translates into real world performance outside of benchmarks will be hardly tangible too, while pci 3.0 will enable you if you wish to SLI or xfire with both cards running at 16X PCIE 2.0 bandwidth even on the cheaper motherboards.
