1 vs 2 Phase AUX Power

[Melodist]

What's the difference between 1 and 2 x Phase AUX Powers?

[thrasher_565]

36 minutes ago, Melodist said:

What's the difference between 1 and 2 x Phase AUX Powers?

one use more amps then the other, once something gets spinning it needs less power to keep it spinning so it switches to a different power that use less. but the one that uses less dose not have enough to get the thing spining.

 

unless we are talking about something els?

Edited September 30, 2023 by thrasher_565

[mariushm]

More phases  can mean smoother output voltage, faster reaction time to fluctuations in power consumption, but may result in lower efficiency

It doesn't always mean more current, for example one could use a 70-90A power stage in the one phase aux and another board could use 2 40A power stages in the 2 phase aux.

 

An AUX voltage is just that, auxiliary, used for less critical stuff, stuff that doesn't fluctuate a lot in power consumption and it should not be a high current amount.. so being one phase or two, should not be that important when it comes to selecting a motherboard for purchase.

[Melodist]

1 hour ago, mariushm said:

More phases  can mean smoother output voltage, faster reaction time to fluctuations in power consumption, but may result in lower efficiency

It doesn't always mean more current, for example one could use a 70-90A power stage in the one phase aux and another board could use 2 40A power stages in the 2 phase aux.

 

An AUX voltage is just that, auxiliary, used for less critical stuff, stuff that doesn't fluctuate a lot in power consumption and it should not be a high current amount.. so being one phase or two, should not be that important when it comes to selecting a motherboard for purchase.

Because I was reading about the 16+1+2 phase designs.

 

I mean the VRM stage I understand where it's 8 and basically in parallel and 1 for the integrated graphics but the 2 x aux has to do with the 12V input I assume?

 

Does it have to do with 8+4 vs 8+8 connectors where 8+4 is one aux phase and the 8+8 two aux phases?

 

Seeing more 14th gen boards having two phase aux power.

 

I'm wondering whether that'd be a problem with my Asus Proart Z790 Creator when it comes to running a 14900K at it's full boost, although a sticker outside the package says Next Gen CPU ready.

[mariushm]

No, I think aux has something to do with powering the pci-e controller and/or other system-on-chip controllers but I'm not sure... I didn't keep up with these minor rails.

 

The 8 phases for CPU are not in parallel, they can run all at the same time, but usually they're meant to alternate, two - three phases work for some time for example, then others start to work and let the others cool down a bit, and so on... each phase can do let's say up to 80A of current, but they may be most efficient at 30-40A, so instead of using just 4 phases at 50A to produce 200A of current, they can run 6-8 phases at 30-40A to get better efficiency...  if you run all four at same time for 10ms then stop for 1-2ms and rely on the energy stored in inductors and capacitors to provide smooth output voltage, then you may get fluctuations in the voltage, like for example 1.5v when the phases all run and the capacitors are topped out and then during those 1-2ms of off time, the voltage may drop to 1.48v until the phases restart and top up the inductors and capacitors.  If you alternate between phases, there's never a "dead" time, and a few phases are always ready and working to top up and maintain the voltage to the level the cpu asks.