Intel Core i “Haswell” CPUs May Require New Power Supply Units for PCs

It's like how motherboard manufacturers couldn't figure out how to keep the voltage regulators on their boards from overheating in the summer and desoldering themselves.

There are some interesting reasons for that.

When a lot of transistors in an integrated circuit all switch at the same time, it can cause the chip's power and ground voltage levels to shift, relative to the circuit board's power and ground levels. The size of the difference depends on the inductance between the chip and board, i.e. the inductance of the chip's power and ground pins. Inductance can be minimized by connecting a lot of inductors in parallel. Lots of small pins are better than a few big ones.

If the inductance is too high and the chip's power voltage falls below its ground voltage, this will randomize every storage element on the chip. The rule of thumb is that a third of the pins need to be power or ground.

Not likely. The problem is that the PSU will shut down (self protection) if it has less that its minimum current draw. It has to do this because the voltage regulation loop goes unstable if it was designed to have a higher minimum current draw. If the PSU didn't shut down, it would fry things, including itself. Really bad.

To test the PSU works at 0.5A would end up shutting down the computer if the PSU didn't work at 0.05A... exactly what happens today. Unfortunately, at that point it is too late to tell the user "your PSU is old" or to quickly connect a resistor across the +12v rails to work around the problem.

As an experiment, find an old PSU and plug it into the wall (nothing connected to the power output connectors). It won't power on. If you connect a 2 ohm 10W resistor (or two 1 ohm 5W resistors in series) into the "hard drive" Molex connector +12v (yellow) to ground (black), it should start up and be happy.

Disclaimers:

1) The resistor will become quite warm quite quickly (6W), watch your fingers.

2) If you damage something, it is a learning experience, not my fault.

You're implying it could be done if whatever load distribution and power condition that's done outside of the chip, which consists of a lot of analog components to help manage rapid changes in power consumption, could be somehow packaged inside the chip.

So, in rough terms, the internals of a large-scale chip are not one big integrated circuit, but a large number of smaller modules that are massively interconnected, then?

That rule of thumb seems to apply to only a particular class of chips. Wouldn't the number of pins be somehow proportional to the power draw, as at higher currents induction would become a more severe problem? It's just usually the case that more power-hungry chips have more pins, as the 2011 socket is for Intel's flagship CPUs, the 1155 ones more commodity-oriented.

With the power voltage dropping below ground, that unless you had a floating ground, that'd be implying reverse flow of current, negative voltage, right? Or are you talking about a non-zero voltage ground? I'm not sure what the presumption is in real-world CPU design.

Where to start. Multiple pins supplying power to a die isn't done because they can't clonk a pair of big connectors in the middle. The resistance within the die would cause different ground levels and voltage drops if supplied at only one physical location. The PCB has much more space for "thick" copper traces (complete ground plane) and buffer caps to supply a stable voltage across the entire die.

Second, CPUs have a dedicated 12V rail on the MB since quite some time. It's plugged in right near the voltage regulators of the CPU.

Third, a GPU die also has multiple power rails and distribution over the die as CPUs. Given the insane power requirements and transistor count, they likely have even more. The same is true for other power hungry ICs, for example high-speed DSPs, FPGAs, image sensors and so on.

Fourth, PCI/PCIe can't carry hundredths of watts, it would not be cost effective to kit out PCs with heavy duty connectors and thick main board traces just because one or two slots may one day be used for a space heater. Thus another dedicated rail from the PSU.