Credit to onQ123 from neogaf.
"[0019] This structure of the electronic equipment 1 eliminates the need for a space for a heat radiating apparatus on the upper side of the integrated circuit apparatus 5 as illustrated in FIG. 1, thus making it possible to dispose another component 9 (e.g., a transmission/reception module with an antenna and so on, a sensor, an external storage apparatus) of the electronic equipment 1 on the upper side of the integrated circuit apparatus 5 and ensuring a higher degree of freedom in laying out the component 9. In the example of the electronic equipment 1, the component 9 is disposed on the opposite side of the heatsink 21 with the circuit board 10 and the integrated circuit apparatus 5 provided therebetween. That is, the component 9 is disposed close to the upper side of the integrated circuit apparatus 5. Specifically, a distance L1 between the component 9 and the integrated circuit apparatus 5 is smaller than a height H1 of the heatsink 21. Unlike the example of the electronic equipment 1, another heat radiating apparatus may be provided on the upper surface of the integrated circuit apparatus 5. As a result, two heat radiating apparatuses are provided on the integrated circuit apparatus 5, thus providing improved cooling performance. "
So what is all this?
Well its this:
but also this:
Credit to Dontero (neogaf):
green - PCB
orange - heatsink/heatpipes
blue - main chip with housing
Basically chip is placed not on PCB but on heatplate that heatplate has miniheatpipes coming throught it on other side of pcb where lies heatsink with fins. center of chip is used to cool via heatplate and PCI lanes go around the rim of chip. Consoles don't need a lot of PCI lanes so it is perfectly reasonable that a lot of underside is without PCI lanes unlike something like PC chip. Then there is other heatsink which lies on top of housing with paste in traditional way.
neat design, but i doubt it would poliferate to PC as PC chips have massive amount of PCI lanes and there is simply no space for heatplate. With such setup you can cool chip from two sides which is especially important for 3D stacked chips.
Why do it like this? This seems over complicated, you might say.
The 3D stacking of chips allows you to "move" units of the chip closer to one another, so flow between parts is shorten, and thus you achieve a saveing in power draw (it uses less power this way), shorter distance to move data around can also results in speedups and lower latency when doing so.
Another benefit is, it appears they are able to have a "cooling unit" on each side of the chip, this way.
Which might result in a more effecient way to cool down the chip.
So whats the draw back?
This is probably abit more expensive than doing it the normal way.
