What's all this "phase" stuff?

Often see motherboards showing off "8 phase", "12 phase", etc... What exactly is that, and what benefit does it give to the user? Not quite sure myself. I know that the "phases" are the little black cubes by the CPU, but not exactly sure what they do.

JonSimonzi said:

Often see motherboards showing off "8 phase", "12 phase", etc... What exactly is that, and what benefit does it give to the user? Not quite sure myself. I know that the "phases" are the little black cubes by the CPU, but not exactly sure what they do.

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This is a good article by an EE explaining that: http://www.improbableinsights.com/2009/08/28/do-i-need-32-phase-power-on-my-motherboard/

"Phases" in the sense you mention is a marketing term, ignore the hype around it completely. Each phase is a stage of power regulation and filtering, the link above explains the basic principles. Most of the boards out that tout "8 CPU phases" are 4 phase and those touting "12 CPU phases" are 6 phase, in fact. All the MFGs do is add 2 inductors per phase and call that another phase to dupe lay consumers - more is better principle. In reality, a well designed 4 phase CPU VRM is enough for anything and usually better than any of the lower/higher offerings (remember we've already had Prescott). Any good quality 2+1/2+2 MOS per phase board with 1/2 inductors per phase and some good caps will be hard to beat in terms of clean power/stability/efficiency.

You have to keep in mind that the MOSFETs/capacitors/inductors used on MB VRMs can be of significantly different quality. That is why some are highly efficient while others very inefficient. Some can handle 40A per phase while others only 15A. The inefficient ones run hotter and waste the most energy so they will increase the CPUs 12v power consumption too.

Also keep in mind that chipsets and memory also have multi-phase regulation nowadays.

even more basic than that: know that more is better, and that unless you are doing extreme overclocking (sending very high voltages to the processor and using dry ice or liquid nitrogen) then you typically don't need to be concerned with how many phases your motherboard has.