Guys, the link in the original post... the first graph that comes up when you click that link is power consumption for various CPUs at different frequencies.
This first graph clearly shows IVB at it's max stable OC (4.8 GHz) drawing less than SB @ 5.2 GHz. Both are at their max stable overclocks.
Then the very next graph shows IVB at 20C higher temperature.
EDIT: TT appears to have changed their graph to remove the SB 2600k @ overclocked speed, when it was there before, it showed higher power consumption at significantly lower temperature. I'm not sure why they removed it, but it used to be there. You'll note that the link to the picture in the OP appears to be broken, this is because they changed the picture to remove the 2600k @ overclocked. Something fishy is going on at TT.
IVB is getting to a significantly higher temperature while producing less heat.
Read that last sentence again and again, and you will come to the same conclusion I did. The cause of the high temperature cannot possibly be leaky gates. Leaky gates waste electrical energy as heat... power consumption would be high, but it is not high.
There are three possible explanations for this:
1) thermal gradient is worse. Material between the heatsink and the source of the heat is less conductive than the SB design. This is possible if the fin-fet transistors are somehow deeper into the filmstack of the material on top is less conductive than the SB design. I don't pretend to have any clue as to the design here, but fin-fet is a major departure from conventional processes, and they may have had to alter materials throughout the stack to pull it off.
In layman's terms, this potential cause is much like a person in a cool house in shorts and a t-shirt vs. the same person in a bed with a pile of sheets and blankets covering them. The body is putting out the same amount of heat energy, the air (heatsink) is the same temperature, but in one case the body is cold and in the other it is comfortably warm.
2) Density is significantly higher. This is also possible because we know:
- The process is smaller
- The IGP has been given a higher percentage of total die area than on SB
- The die is smaller than SB (according to Wikipedia 216mm2 vs ~160mm2 fo IVB)
These could all result in the heat being dispersed over less area.
The obvious example here is 10 people spread comfortably throughout a 2500 square foot house vs. 10 people in a closet. 10 people put out a reasonably similar amount of heat in either case, but 10 people in a closet will get warmer than 10 people spread throughout the entire house.
3) It's possible that the thermal sensor has been put closer to the source or has been redesigned to be more sensitive than the sensor in SB.
- I find this one not so likely, but it's technically a possible reason. If it's closer to the source, then the same thermal gradient would produce higher temperatures.
In any of these cases, the available data does NOT suggest that IVB is leaky. Leaky would shoot power consumption and heat up. Power consumption is not high, only temperature.
This suggests there is an impediment to heat being removed rather than IVB being a major source of heat energy like some other CPU designs (Bulldozer, netburst P4) which DID have major power consumption to go along with their higher temperatures.