6 phase vs 4 phase

khurios2000

Diamond Member
Dec 11, 2003
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Does 4 phase motherboards has lower power consumption consumption than 8 phase?

i just read a few articles regarding AMD X2 3800+ EE, than actually seem to be higher in power consumption in 6 phase compare to 4 phase

also i found this on anandtech regarding a8n32-sli
One of the main design features that Asus engineered into this board is an exclusive 8-phase voltage regulator power design that can significantly lower operating temperatures while reducing input ripple current and output ripple voltages . In fact, the input ripple current is over three times lower than a traditional 4-phase design while output ripple voltages are four times lower. The power consumption compared to the 4-phase design is about 10% less while the 8-phase design has the advantage of quicker transient responses and increased dependability due to lower thermal values.

my question is does more phases in motherboard will affect power consumption?
 

BrownTown

Diamond Member
Dec 1, 2005
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More phases are for power quality more than power consumption, you get less ripple which means better quality power. This can also translate into needing slightly less voltage to achieve the same clockspeed which would mean less power consumption. Not sure how much the MOSFETS themselves use on a motherboard, but I doubt it can be all that signifigant compared to the draw of the processor.
 

Mark R

Diamond Member
Oct 9, 1999
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There will be a marginal improvement in power consumption, with more phases.

Adding more phases spreads the current through more MOSFETs. As power = I^2 x R, then reducing the current by half through each MOSFET (by doubling the number) reduces each MOSFET's power consumtion to a quarter, and the total power consumption of all the MOSFETs by half.

However, total power consumption of the voltage regulator is marginal - maybe 10-15 W at full load. Increasing the number of MOSFETs requires careful design, as adding more can raise the idle power consumption.