Motherboard power: Digital PWM, 16 phase, etc.

[eddieck]

I've currently got the P6T SE board, and I am looking to upgrade it for SLI support. The closest option I can see is the P6T which is very similar (same layout and all), just with an extra JMicron controller and SLI support.

One thing I've noticed between boards though is their power delivery systems. The P6T SE and P6T vanilla boards both have 8 phase power. The Deluxe, on the other hand, has 16 phase power. Other boards like the Rampage III series or the EVGA Classified offer 8 phase digital PWM.

For someone who is only planning on air or water overclocks (no LN2, DICE, phase change), is there any difference at all between 8 phase and 16 phase? What makes the 16 phase or digital PWM options a better option? I suppose what I'm asking is if I should buy a more expensive board because of a "superior" power delivery system, versus a less expensive board that still has all the features I need (with regards to slot layout, SLI, ports) but with an inferior power delivery system.

 

[MrWizard6600]

powered by a Seasonic M12D?

I wouldn't worry about it, from a power regulation standpoint, go for the cheaper Asus boards.

From an overall quality of the board standpoint I'm making no assertions on anything. Not all boards with the same chip-set clock alike: I remember the LGA 775 BI boards from DFI were out-clocking all the ROG stuff.

But there really isn't a whole lot of point in adding SLI after the fact. By the time you roll around to picking up a second card, it's going to be more economical to just buy a new card from the latest generation.

 

[eddieck]

powered by a Seasonic M12D?

I wouldn't worry about it, from a power regulation standpoint, go for the cheaper Asus boards.

From an overall quality of the board standpoint I'm making no assertions on anything. Not all boards with the same chip-set clock alike: I remember the LGA 775 BI boards from DFI were out-clocking all the ROG stuff.

But there really isn't a whole lot of point in adding SLI after the fact. By the time you roll around to picking up a second card, it's going to be more economical to just buy a new card from the latest generation.

I'm actually using an S12D 850W. And I am planning on going SLI now, either with dual GTX 460s or GTX 470s if I can find them cheap enough.

 

[BillParrish]

after 4 phases its more about the implementation and quality of the components used than the number of phases. I would be looking at the cooling (heatsinks/heatpipe) for the mosfets more than the number of phases.

Couple of years ago it would have mattered as there where still a lot of enthusiast boards with so-so cpu voltage regulation circuitry and the old style Aluminum electrolytic caps which where the big problem. More phases, among other things, reduces the ripple current on the caps and they where more reliable in high phase count systems. (MosFETS are power devices and are pretty rugged, designed for high power and high temps - but cooler is always better) Now with the solid electrolyte caps and a decent number of phases almost any enthusiast board, except perhaps at the very low end or boards designed for HTPC use, have a good enough cpu voltage regulation circuit to do about anything the cpu is capable of. Adding a spare case fan positioned to blow air directly over those components if the stock intel heatsink is not used will provide extra insurance for a long reliable, stable overclock.


It annoys me that manuf have gotten into a # of phases war but seldom document the engineering reason their design is better from a technical view. If they give us anything its some marketing blurb that is pretty thin.

Also keep in mind, chaos theory. The simpler a thing is the less there is to go wrong. Or put another way, it all goes to crap eventually but the more of it there is the more likely it will happen sooner.

edit: oh but a digital PWM controller chip is desirable. I would guess, because I have not checked, that all the middle and high end board use them but thats a definate + over the older style PWM controller chip. More accurate etc.

So I look for 6+ phases, solid caps are an absolute must and I want all of them everywhere to be solid, and mosfet cooling. (assuming OCing).

edit 2:

oh and the 2oz copper PCB is a real quality and thermal improvement. I like Gigabytemes for that. Other manuf may have started using them as well. Our telecom DC power supplies always used 2oz copper PCB's even 20 years ago for improved current carrying capacity of a trace with less voltage loss due to trace resistance and thus less internal board heating.

 

[eddieck]

Great post there Bill!

oh and the 2oz copper PCB is a real quality and thermal improvement. I like Gigabytemes for that. Other manuf may have started using them as well. Our telecom DC power supplies always used 2oz copper PCB's even 20 years ago for improved current carrying capacity of a trace with less voltage loss due to trace resistance and thus less internal board heating.

ASUS does it now on all their newer boards (P6TD Deluxe, P6X58D, R3). I would also assume MSI does with their latest military-standard push, but can't confirm that.

 

[Dan_D]

after 4 phases its more about the implementation and quality of the components used than the number of phases. I would be looking at the cooling (heatsinks/heatpipe) for the mosfets more than the number of phases.

Couple of years ago it would have mattered as there where still a lot of enthusiast boards with so-so cpu voltage regulation circuitry and the old style Aluminum electrolytic caps which where the big problem. More phases, among other things, reduces the ripple current on the caps and they where more reliable in high phase count systems. (MosFETS are power devices and are pretty rugged, designed for high power and high temps - but cooler is always better) Now with the solid electrolyte caps and a decent number of phases almost any enthusiast board, except perhaps at the very low end or boards designed for HTPC use, have a good enough cpu voltage regulation circuit to do about anything the cpu is capable of. Adding a spare case fan positioned to blow air directly over those components if the stock intel heatsink is not used will provide extra insurance for a long reliable, stable overclock.


It annoys me that manuf have gotten into a # of phases war but seldom document the engineering reason their design is better from a technical view. If they give us anything its some marketing blurb that is pretty thin.

Also keep in mind, chaos theory. The simpler a thing is the less there is to go wrong. Or put another way, it all goes to crap eventually but the more of it there is the more likely it will happen sooner.

edit: oh but a digital PWM controller chip is desirable. I would guess, because I have not checked, that all the middle and high end board use them but thats a definate + over the older style PWM controller chip. More accurate etc.

So I look for 6+ phases, solid caps are an absolute must and I want all of them everywhere to be solid, and mosfet cooling. (assuming OCing).

edit 2:

oh and the 2oz copper PCB is a real quality and thermal improvement. I like Gigabytemes for that. Other manuf may have started using them as well. Our telecom DC power supplies always used 2oz copper PCB's even 20 years ago for improved current carrying capacity of a trace with less voltage loss due to trace resistance and thus less internal board heating.

Pretty much all of this. It really comes down to the quality of the components used and their implementation. I've seen boards with 4 phase power overclock well and boards with 16 or more phases suck at it.