What is the deal with various 4+1/8+2/8+1 Phase Power Design
on AMD AM2+/AM3 boards.
What are the pros/cons of 8+2(8+1) over 4+1.
Is 4+1 (Asus M3A78-T) still ok for 940BE when overclocking
or should I consider 8+2(8+1) boards?
What is the deal with various 4+1/8+2/8+1 Phase Power Design
on AMD AM2+/AM3 boards.
What are the pros/cons of 8+2(8+1) over 4+1.
Is 4+1 (Asus M3A78-T) still ok for 940BE when overclocking
or should I consider 8+2(8+1) boards?
Last edited by Bladesinger7x; 02-13-2009 at 05:07 AM.
AsRock Z68 Extreme3 Gen3 / i5 2500k / 8 GB Corsair Vengeance / Sapphire HD6850 / Crucial M4 64 + Samsung F3 500GB + F1 640GB / Corsair HX750 / CPU / GPU H2O / Sharkoon Seraphim rev.ATX
8 + phase when implemented correctly requires less power to acchieve clocks,its cleaner power, it's not as stressfull on PSU, and is considered to have a longer longevity. I might add there are very few true 8 phase designs. Most are split 4 + 4.
4 + works, if properly implemented and kept cool, if not it will eventually blow up when pushed hard.
heatware chew*
I've got no strings to hold me down.
To make me fret, or make me frown.
I had strings but now I'm free.
There are no strings on me
Well the CPU (and GPU) will be under water so no additional
airflow will be coming from the CPU fan, however, I do have
a 250mm fan on the case side (Sharkoon Seraphim case).
I doubt I will overclock the CPU by much (if at all) so 4+1
should be fine?
What is the verdict on Asus M3A78-T pwm design? Ok or not.
Or should I wait for the M4A78-E which has 8+1 design?
AsRock Z68 Extreme3 Gen3 / i5 2500k / 8 GB Corsair Vengeance / Sapphire HD6850 / Crucial M4 64 + Samsung F3 500GB + F1 640GB / Corsair HX750 / CPU / GPU H2O / Sharkoon Seraphim rev.ATX
Preety sure they are all 4 + 4, ATI made a true 6 phase back in the 939 days.
heatware chew*
I've got no strings to hold me down.
To make me fret, or make me frown.
I had strings but now I'm free.
There are no strings on me
heatware chew*
I've got no strings to hold me down.
To make me fret, or make me frown.
I had strings but now I'm free.
There are no strings on me
so then what is the big difference between 4+4+2 and a TRUE 8+2. I understand that is has to do with voltage ripple and the more phases the less voltage ripple.
heatware chew*
I've got no strings to hold me down.
To make me fret, or make me frown.
I had strings but now I'm free.
There are no strings on me
heatware chew*
I've got no strings to hold me down.
To make me fret, or make me frown.
I had strings but now I'm free.
There are no strings on me
Allright, let me clear things up.
I have asked a similar question long time ago over at amdzone forums.
http://www.amdzone.com/phpbb3/viewto...140825#p140825
quote:
Time to whip out my electronic circuits textbook...
The topic is not that simple, an 8-phase or 10-phase supply won't always be better than a 5-phase supply. The switches and other parts used in the 8-phase supply you mentioned are not identical to the ones used in the 5-phase AMD boards. The 8-phase parts probably cost less and are much smaller. Both phase supply setups can meet the same requirements regardless of how many phases you use, it just depends mostly on how much you want to spend per part, how much space you have to work with, heat dissipation, your typical design problems. The 8-phase switchers can be cheaper and smaller parts because they will not be stressed as hard as if they were in a 5-phase setup. Also, the phase IC's AMD uses are special, in that they can dynamically change the number of phases depending on how much juice the cpu is asking for, so there is probably no leeway for motherboard designers to create a gimmick board with a 16 phase power supply to woo the enthusiast crowd. I remember reading that the AMD IC's weren't designed for anything more than a 6-phase setup because anything more than that is completely unnecessary for the K8 and K10, and the only reason for having the option of 6 was for extreme overclocking. Considering this, I'd assume that unless you OC the chip enough, it's going to be using 5-phases under load with a 140 watt chip, so 5 will probably be overkill for 99% of the market. 4 and 3 phase boards are meant be paired with a budget processor or a more power friendly Deneb.
end quote
this should sum it up it perfectly.
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AMD Phenom II 1090T @ 4GHz Asus Crosshair IV
HD6970
LSI Megaraid 9260-4i 4xMomentus XT
OCZ Vertex 3@SB850
8 gig Patriot Viper 7-7-7-24 T1
Swiftech Watercooling
Filco Majestouch 2
Zowie EC1
--------------------------------------------------
the dfi m2r hast 6+1 phase design... and i think its true 6+1
1. ASUS Sabertooth 990fx | FX 8320 || 2. DFI DK 790FXB-M3H5 | X4 810
8GB Samsung 30nm DDR3-2000 9-10-10-28 || 4GB PSC DDR3-1333 6-7-6-21
Corsair TX750W | Sapphire 6970 2GB || BeQuiet PurePower 450w | HD 4850
EK Supreme | AC aquagratix | Laing Pro | MoRa 2 || Aircooled
Unless the board manuf. states how many phases a board has, how can you tell? Count the mosfets or chokes?
Phenom II 720 X3 at 222x16 unlocked quad / lapped AC Freezer64 / Gigabyte GA-MA790XT-UD4P / Corsair XMS3 DHX 4GB (2 x 2GB) DDR3 1600MHz / OCZ Vertex 60GB, 74GB Raptor, Seagate 7200.10 250GB / 2x Sapphire 6850 in Crossfire / Coolermaster Mystique / OCZ 700W
Well.. to really know you need to check what VRM controller chip is being used and then pull out the datasheet.
The Vdroop is shouldn't have anything to do with how many phases there is. There are couple reasons for the droop. Most common is the voltage drop caused by copper (resistance) loss in the motherboard. Second is that some PSU have "programmed droop" where voltage drops linearly with function of current. (IIRC, Intel specifies this method for its CPU's to improve dynamic load behavior.)
Droop can be compensated if you take the VRM voltage feedback at the end of the load chain. (Like directly under the CPU.) The drawback is that during dynamic loading the voltage does overshoot and undershoot more than with "programmed droop". This is caused by the limited loop bandwidth of the VRM control loop where it can not respond fast enough for the changed load conditions. Ultimately the LC-filter used in all VRM outputs has a pole frequency that is very low when compared to the required load change speed.
Gigabyte GA-MA790GP-DS4H
Phenom II 940 (0850DPMW) @3.55GHz, 1.375V
Kingston HyperX 2x 2GB PC8500 (5-5-5-15) @948, 2.0V
MSI Radeon HD4870 1GB @790/1000
Xigmatek HDT-S1284EE
150GB VelociRaptor (system disk)
750GB WD 7500AAKS (data disk)
8+2 phase power on Asus M4A79T Del. (thats their word)..
Try overclock voltages in bios, see if there vdroop or instability.
Some mobo can't take high vcore for long benching session.
What usually works is counting the number of chokes.
e.g. 10 chokes = 10 phases = 8 + 2 most likely
In the picture of the asus board from Dumo, they are labled YAGEO 1R2
or TRIO R47 in another picture.
--------------------------------------------------
AMD Phenom II 1090T @ 4GHz Asus Crosshair IV
HD6970
LSI Megaraid 9260-4i 4xMomentus XT
OCZ Vertex 3@SB850
8 gig Patriot Viper 7-7-7-24 T1
Swiftech Watercooling
Filco Majestouch 2
Zowie EC1
--------------------------------------------------
Nice pic of magic smoke production.
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