Overclock.net › Forums › Components › Power Supplies › FAQ: Dual Power Supplies
New Posts  All Forums:Forum Nav:

FAQ: Dual Power Supplies

post #1 of 59
Thread Starter 
The short answer: Don't.


The vast majority of people who use two power supplies don't need to, and waste money or endanger their rigs doing so. It's only a valid approach in a very small handful of scenarios, and is otherwise either an unnecessary over-complication, or a dangerous jury rig solution.

The main thing people do wrong with dual power supplies is to think they even need it. They look at a GTX580, then look at power consumption charts and think "OMG 500W OMG OMG NEED MOAR POWER" when in fact that's the total system power consumption; the card itself only pulls ~300W. So then they decide to supplement their already more-than-sufficient 650-850W PSU with another PSU, wasting money and making life more difficult, what with having to stash another PSU somewhere inside their case and hiding a bunch more cables.

The next worse thing people do is do dual PSUs with cheap units. Most power supplies under $100, and all under $50, use a technology called "group regulation" to reduce costs. There's a bunch of technical stuff I could throw at you; but the gist of it is that the current on the +12V and +5V rails on a group regulated power supply must stay within a certain approximate ratio to one another (say 3A of +12V for every 1A of +5V, +/-20%) or else the voltage regulation will go out of whack. +12V load too low? +5V voltage drops and +12V voltage soars. +5V load too low? +5V soars and +12V drops.

The secondary PSU in a dual-PSU usually has no +5V load at all, or at most 1-2A, meaning that the +12V voltage will droop significantly; on high-end group regulated units it will fall to 11.6-11.7V, which is in-spec but poor. On low-end group regulated units +12V might drop to 11.3-11.5V, out of spec or almost. Out of spec voltage (>11.4V) can cause component malfunction; bluescreens and random shut downs, and will prevent many hard drives from functioning at all.. Very low, but in-spec voltage (11.4-11.6V) can cause poor overclocking results, occasional instability, excessive wear on component power circuitry, and can cause hard drive issues over time.



Dual PSUs should only be used when both power supplies are high quality and use independent regulation, or even better "DC-DC" regulation. It's only a useful approach when dealing with systems that pull >1000W; then two quality 650W+ indy/DC-DC regulated units may be used in place of a single 1000W+ unit. Even then you may run into issues of crosstalk leading to greater effective ripple on power regulated devices (motherboard, graphics card, RAID controllers), and units that rely on +12V v-sense may suffer poor voltage regulation if the cable with their v-sense wires is not in use.



So just don't.
Edited by Phaedrus2129 - 12/1/11 at 9:16pm
post #2 of 59
Well written, high quality content. Well done. I always look forward to content like this. smile.gif
   
Dream PC
(26 items)
 
CPUMotherboardGraphicsRAM
Intel i7 2600k Asus Maximus IV Extreme-Z Asus GTX 570 Direct CU II [1280MB] G.Skill RipjawsX 1600MHz 9-9-9-24 4x4GB [16GB] 
Hard DriveHard DriveHard DriveHard Drive
Crucial M4 aM4azing SSD [64GB] Kingston HyperX HypersoniX SSD [120GB] Kingston SSDNow V100+ 6Gb/s SSD [60GB] Seagate 7200RPM HDD [1TB] 
Optical DriveCoolingCoolingOS
Samsung DVD Drive Noctua NH-D14 AeroCool Shark case fan Windows 7 Home Premium 64-Bit 
MonitorMonitorKeyboardPower
Yamakasi Catleap Q270 LED 27" IPS Display Samsung SyncMaster 2033 23" secondary utility d... Das Model S Ultimate Silent Corsair AX-850 
CaseMouseMouse PadAudio
HAF X Steelseries Sensei [RAW] Rubberised AG Holomat Interdyn P1.5 Hi-Fi speakers 
AudioAudioAudio
Rotel R8-9608X amplifier Lexicon Lambda Audio Interface Grado SR125i 
CPUMotherboardGraphicsRAM
Intel i7 2600k Asus Maximus IV Extreme-Z EVGA GTX 880 G.Skill RipjawsX 1600MHz 9-9-9-24 4x4GB [16GB] 
Hard DriveHard DriveHard DriveHard Drive
Crucial M4 aM4azing SSD [64GB] Kingston HyperX HypersoniX SSD [120GB] Kingston V200+ SSD [64GB] Seagate SpinPoint 7200.12 [1TB, 2x500GB partiti... 
Optical DriveCoolingCoolingCooling
Super Writemaster DVD Drive Arqtik 180SDD TEC Arqtik Single TEC Controller AquaComputer AquagraFX GTX880 Waterblock 
CoolingCoolingCoolingCooling
XSPC RS360 Koolance PMP-450 Bitspower G/14 compression fittings - Matte bla... PrimoChill PrimoFlex Tubing (7/16x5/8) 
CoolingCoolingOSMonitor
FrozenQ Liquid Fusion V Series 250 ml Reservoir... 3xScythe 120mm SlipStream 1900rpm Fan Windows 9 - Home edition Catleap Q270 LED Primary S-IPS display 
MonitorKeyboardPowerCase
Samsung SyncMaster 2033 secondary utility display Das Model S Ultimate Silent Corsair AX-850 Coolermaster HAF-X 
MouseMouse PadAudioAudio
Steelseries Sensei AG Holomat Interdyn Hi-Fi speakers Rotel R8-960BX Amplifier 
AudioOtherOther
Lexicon Lambda USB Audio Interface with Phantom... CF Wrap :p 3x PrimoChill Anti-Microbial tube coil 
CPUMotherboardGraphicsRAM
Intel Xeon E7-8870 [10 Cores OC'd @ 3.4GHz] Asus Z9PE-D8 WS 4x MSI 680 Lightning 4GB [4-way SLI] Corsair Dominator Platinum 32GB (8x4GB) 
Hard DriveOptical DriveOptical DriveCooling
OCZ Z-Drive R4 CloudServ (3.2TB) Blu-Ray USB Replicator Blu-Ray drive EK HF Supreme Waterblock 
CoolingCoolingCoolingCooling
EK FC680 DCUII Waterblock [x3] EK Rampage IV Extreme Waterblock 3xXSPC RX480 [1x480 for CPU] [2x480 for GPU] 1xXSPC RX240 [For motherboard waterblock] 
CoolingCoolingOSOS
2xFrozenQ liquid fusion 400mm [1 for each loop] 6x Laing D5 [4x for CPU+GPU waterblock] [2x for... Windows 7 Ultimate 64-bit Linux Ubuntu 
MonitorKeyboardPowerCase
3xYakamasi Catleap [OCN Edition] Ducky Shine OCN edition [Blank keycaps] [Red] 2xAX1200 Case Labs Magnum M10 
MouseMouse PadAudioAudio
SteelSeries Sensei XTracPads Ripper XXL 2xMartin Logan CLX Art Electrostatic Speakers [... Krell Evolution One Amplifier 
AudioOther
Allen & Heath GS-R24 Mixing desk Custom made desk 
  hide details  
Reply
   
Dream PC
(26 items)
 
CPUMotherboardGraphicsRAM
Intel i7 2600k Asus Maximus IV Extreme-Z Asus GTX 570 Direct CU II [1280MB] G.Skill RipjawsX 1600MHz 9-9-9-24 4x4GB [16GB] 
Hard DriveHard DriveHard DriveHard Drive
Crucial M4 aM4azing SSD [64GB] Kingston HyperX HypersoniX SSD [120GB] Kingston SSDNow V100+ 6Gb/s SSD [60GB] Seagate 7200RPM HDD [1TB] 
Optical DriveCoolingCoolingOS
Samsung DVD Drive Noctua NH-D14 AeroCool Shark case fan Windows 7 Home Premium 64-Bit 
MonitorMonitorKeyboardPower
Yamakasi Catleap Q270 LED 27" IPS Display Samsung SyncMaster 2033 23" secondary utility d... Das Model S Ultimate Silent Corsair AX-850 
CaseMouseMouse PadAudio
HAF X Steelseries Sensei [RAW] Rubberised AG Holomat Interdyn P1.5 Hi-Fi speakers 
AudioAudioAudio
Rotel R8-9608X amplifier Lexicon Lambda Audio Interface Grado SR125i 
CPUMotherboardGraphicsRAM
Intel i7 2600k Asus Maximus IV Extreme-Z EVGA GTX 880 G.Skill RipjawsX 1600MHz 9-9-9-24 4x4GB [16GB] 
Hard DriveHard DriveHard DriveHard Drive
Crucial M4 aM4azing SSD [64GB] Kingston HyperX HypersoniX SSD [120GB] Kingston V200+ SSD [64GB] Seagate SpinPoint 7200.12 [1TB, 2x500GB partiti... 
Optical DriveCoolingCoolingCooling
Super Writemaster DVD Drive Arqtik 180SDD TEC Arqtik Single TEC Controller AquaComputer AquagraFX GTX880 Waterblock 
CoolingCoolingCoolingCooling
XSPC RS360 Koolance PMP-450 Bitspower G/14 compression fittings - Matte bla... PrimoChill PrimoFlex Tubing (7/16x5/8) 
CoolingCoolingOSMonitor
FrozenQ Liquid Fusion V Series 250 ml Reservoir... 3xScythe 120mm SlipStream 1900rpm Fan Windows 9 - Home edition Catleap Q270 LED Primary S-IPS display 
MonitorKeyboardPowerCase
Samsung SyncMaster 2033 secondary utility display Das Model S Ultimate Silent Corsair AX-850 Coolermaster HAF-X 
MouseMouse PadAudioAudio
Steelseries Sensei AG Holomat Interdyn Hi-Fi speakers Rotel R8-960BX Amplifier 
AudioOtherOther
Lexicon Lambda USB Audio Interface with Phantom... CF Wrap :p 3x PrimoChill Anti-Microbial tube coil 
CPUMotherboardGraphicsRAM
Intel Xeon E7-8870 [10 Cores OC'd @ 3.4GHz] Asus Z9PE-D8 WS 4x MSI 680 Lightning 4GB [4-way SLI] Corsair Dominator Platinum 32GB (8x4GB) 
Hard DriveOptical DriveOptical DriveCooling
OCZ Z-Drive R4 CloudServ (3.2TB) Blu-Ray USB Replicator Blu-Ray drive EK HF Supreme Waterblock 
CoolingCoolingCoolingCooling
EK FC680 DCUII Waterblock [x3] EK Rampage IV Extreme Waterblock 3xXSPC RX480 [1x480 for CPU] [2x480 for GPU] 1xXSPC RX240 [For motherboard waterblock] 
CoolingCoolingOSOS
2xFrozenQ liquid fusion 400mm [1 for each loop] 6x Laing D5 [4x for CPU+GPU waterblock] [2x for... Windows 7 Ultimate 64-bit Linux Ubuntu 
MonitorKeyboardPowerCase
3xYakamasi Catleap [OCN Edition] Ducky Shine OCN edition [Blank keycaps] [Red] 2xAX1200 Case Labs Magnum M10 
MouseMouse PadAudioAudio
SteelSeries Sensei XTracPads Ripper XXL 2xMartin Logan CLX Art Electrostatic Speakers [... Krell Evolution One Amplifier 
AudioOther
Allen & Heath GS-R24 Mixing desk Custom made desk 
  hide details  
Reply
post #3 of 59
Thanks man! I can't believe I was thinking of doing this.
Asus G74Sx-BBK8
(10 items)
 
   
CPUMotherboardGraphicsRAM
Intel Core i7 2670QM G74Sx-BBK8 NVIDIA GeForce GTX 560M 2gb Overclocked 2x4gb Samsung 1333MHz 
Hard DriveHard DriveOptical DriveOS
WD Scorpio Black 500gb WD Scorpio Black 500gb Slimtype DVD Writer Windows 7 Home Premium x64 
MonitorMouse
17.3" 1600x900 Logitech M515 
CPUMotherboardGraphicsRAM
Intel Pentium T2080 Toshiba A135 Intel 945gma 2gb DDR2 
Hard DriveOptical DriveOSMonitor
120gb Fitjitsu Matshita DVD-Writer Vista Home Premium x86 15.4" 1280x800 
  hide details  
Reply
Asus G74Sx-BBK8
(10 items)
 
   
CPUMotherboardGraphicsRAM
Intel Core i7 2670QM G74Sx-BBK8 NVIDIA GeForce GTX 560M 2gb Overclocked 2x4gb Samsung 1333MHz 
Hard DriveHard DriveOptical DriveOS
WD Scorpio Black 500gb WD Scorpio Black 500gb Slimtype DVD Writer Windows 7 Home Premium x64 
MonitorMouse
17.3" 1600x900 Logitech M515 
CPUMotherboardGraphicsRAM
Intel Pentium T2080 Toshiba A135 Intel 945gma 2gb DDR2 
Hard DriveOptical DriveOSMonitor
120gb Fitjitsu Matshita DVD-Writer Vista Home Premium x86 15.4" 1280x800 
  hide details  
Reply
post #4 of 59
I'm not intending to contradict what you are saying but what about using one of the (Add2Psu) adapter such as I posted in this thread? http://www.overclock.net/t/1084863/add2psu-dual-psu-adapter-21-99-shipped Then using the additional power for system fans, pumps, possibly additional 8 or 6 pin graphics card connectors. Other than that yes i agree you should not be mixing power supply for main-board, CPU, memory and such.
12 Thread i7x
(19 items)
 
  
CPUMotherboardGraphicsRAM
Intel Core i7 3960X Rampage IV Extreme MSI Radeon 6990 G.Skil F3-170000CL9-4GBZH Ripjaws Z DDR3 2133 
Hard DriveHard DriveHard DriveHard Drive
Crucial M4-CT128M4SSD2 Samsung 830  ST31000528AS ST31000524 
Optical DriveCoolingOSMonitor
Samsung DVDWBD SH-B123L Corsair H80 Windows 7 Pro 64Bit Gateway 24" FD2400 
MonitorMonitorKeyboardPower
Vizio 22" M220VA Vizio 22" E220VA Overclock.net Edition Ducky 1087 10 Key-less Bl... XFX-850 Black Edition 
CaseMouseMouse Pad
HAF - 932 Black Edition Cooler Master Storm Inferno World of Warcraft Cataclysm Collectors Edition 
  hide details  
Reply
12 Thread i7x
(19 items)
 
  
CPUMotherboardGraphicsRAM
Intel Core i7 3960X Rampage IV Extreme MSI Radeon 6990 G.Skil F3-170000CL9-4GBZH Ripjaws Z DDR3 2133 
Hard DriveHard DriveHard DriveHard Drive
Crucial M4-CT128M4SSD2 Samsung 830  ST31000528AS ST31000524 
Optical DriveCoolingOSMonitor
Samsung DVDWBD SH-B123L Corsair H80 Windows 7 Pro 64Bit Gateway 24" FD2400 
MonitorMonitorKeyboardPower
Vizio 22" M220VA Vizio 22" E220VA Overclock.net Edition Ducky 1087 10 Key-less Bl... XFX-850 Black Edition 
CaseMouseMouse Pad
HAF - 932 Black Edition Cooler Master Storm Inferno World of Warcraft Cataclysm Collectors Edition 
  hide details  
Reply
post #5 of 59
Thread Starter 
Quote:
Originally Posted by drufause View Post

I'm not intending to contradict what you are saying but what about using one of the (Add2Psu) adapter such as I posted in this thread? http://www.overclock.net/t/1084863/add2psu-dual-psu-adapter-21-99-shipped Then using the additional power for system fans, pumps, possibly additional 8 or 6 pin graphics card connectors. Other than that yes i agree you should not be mixing power supply for main-board, CPU, memory and such.

Not as dangerous, sure, but still a pain in the ass and usually not even necessary or worthwhile.
post #6 of 59
Phaedrus.

What do you suggest then for people using Quad Nvidia 580 and the new 3930k/3960x that can draw 500w when OCed?

Is there any other choice then using dual-PSU?
    
CPUCPUMotherboardGraphics
i7-3930k @ 5.1  i7-2600k @ 5.3 (2nd rig) Asus Rampage IV (X79) + Asus Maximus Extreme IV... 3X eVGA Titan Tri-SLI  
GraphicsRAMRAMHard Drive
2X Asus DirectCU II Top watercooled (2nd rig)  4X4GB=16GB Ripjaws DDR3 2400 CL9  4X4GB=16GB Ripjaws DDR3 1600 CL7 (2nd rig) Samsung 840 Evo 1TB SSD 
Hard DriveHard DriveHard DriveOptical Drive
Crucial M4 512Gb Crucial M4 256Gb  3XSeagate 2TB LG Blu-ray writer 
CoolingCoolingCoolingCooling
2X Quad-120 MCR420 2X Triple-120 MCR320 + 1X Triple-120 Feser 2X Dual-120 XSPC RX240 32 Gentle Typhoon fans (mix of 3000 and 1850rpm) 
CoolingCoolingOSMonitor
Reservoir 2X Koolance RP-452x2 with 4X MCP655 p... 2X EK Supreme HF CPU waterblock Windows 7 x64 Eyefinity: 3X ZR30W (30'')  
KeyboardPowerCaseMouse
Leopold Tenkeyless 1 Brown 3 Blue, Corsair K90 Antec HCP1200 + AX850 dual PSU main rig, AX120... Mountain Mods Extended Ascension + Pedestal 24 ... Corsair M60 + Razer DeathAdder  
Audio
PSB speakers 5.1 
  hide details  
Reply
    
CPUCPUMotherboardGraphics
i7-3930k @ 5.1  i7-2600k @ 5.3 (2nd rig) Asus Rampage IV (X79) + Asus Maximus Extreme IV... 3X eVGA Titan Tri-SLI  
GraphicsRAMRAMHard Drive
2X Asus DirectCU II Top watercooled (2nd rig)  4X4GB=16GB Ripjaws DDR3 2400 CL9  4X4GB=16GB Ripjaws DDR3 1600 CL7 (2nd rig) Samsung 840 Evo 1TB SSD 
Hard DriveHard DriveHard DriveOptical Drive
Crucial M4 512Gb Crucial M4 256Gb  3XSeagate 2TB LG Blu-ray writer 
CoolingCoolingCoolingCooling
2X Quad-120 MCR420 2X Triple-120 MCR320 + 1X Triple-120 Feser 2X Dual-120 XSPC RX240 32 Gentle Typhoon fans (mix of 3000 and 1850rpm) 
CoolingCoolingOSMonitor
Reservoir 2X Koolance RP-452x2 with 4X MCP655 p... 2X EK Supreme HF CPU waterblock Windows 7 x64 Eyefinity: 3X ZR30W (30'')  
KeyboardPowerCaseMouse
Leopold Tenkeyless 1 Brown 3 Blue, Corsair K90 Antec HCP1200 + AX850 dual PSU main rig, AX120... Mountain Mods Extended Ascension + Pedestal 24 ... Corsair M60 + Razer DeathAdder  
Audio
PSB speakers 5.1 
  hide details  
Reply
post #7 of 59
Thread Starter 
Quote:
Originally Posted by Levesque View Post

Phaedrus.
What do you suggest then for people using Quad Nvidia 580 and the new 3930k/3960x that can draw 500w when OCed?
Is there any other choice then using dual-PSU?

Antec HCP-1200, Corsair AX1200, Thermaltake Toughpower 1350M, Silverstone ST-1500, Enermax Platimax 1200W
post #8 of 59

Good write up. My servers still need their redundant psu's though :p

Gene-Z Dedi
(7 items)
 
Captain America
(6 items)
 
 
CPUMotherboardRAMHard Drive
i7 2600k @ 5.2 Ghz Asus Maximus IV Gene-Z Gskill 2133 4GB Caviar Black 
CoolingOSPower
Corsair H100 Arch x64 OCZ 650 Watt 
CPUCPUMotherboardGraphics
Intel Xeon E5-2650 Intel Xeon E5-2650 ASUS Z9PE-D8 WS XFX 6870 
RAMOS
32 GB Samsung Arch Nix 
  hide details  
Reply
Gene-Z Dedi
(7 items)
 
Captain America
(6 items)
 
 
CPUMotherboardRAMHard Drive
i7 2600k @ 5.2 Ghz Asus Maximus IV Gene-Z Gskill 2133 4GB Caviar Black 
CoolingOSPower
Corsair H100 Arch x64 OCZ 650 Watt 
CPUCPUMotherboardGraphics
Intel Xeon E5-2650 Intel Xeon E5-2650 ASUS Z9PE-D8 WS XFX 6870 
RAMOS
32 GB Samsung Arch Nix 
  hide details  
Reply
post #9 of 59
Thread Starter 
Quote:
Originally Posted by JedixJarf View Post

Good write up. My servers still need their redundant psu's though tongue.gif

Oh yeah, redundant PSUs are totally different. tongue.gif
post #10 of 59
Quote:
Originally Posted by Phaedrus2129 View Post

Antec HCP-1200, Corsair AX1200, Thermaltake Toughpower 1350M, Silverstone ST-1500, Enermax Platimax 1200W

So you think a single AX1200 could do: 4X 580 OC (or 4X Lightning 6970 heavealy OCed), 1X 3930k OC (taking around 500w), 32 Gentle Typhoons fans (6X 3000rpm in those 32), 4 pumps MCP655, 6x 2TB HDD, 3 SSD and 1X Blu-ray writer?

I'm asking this, because I'm trying to use 2 PSUs for this system, and the results are a dead AX1200, and a dead Antech HCP-1200, in the last week. I was trying to pair those with an AX850 with the Add2PSU thingy. But there is 2 dead PSUs, a dead Rampage IV and a dead 3930k in the last week...

I don't know if using 2 PSUs killed the AX1200 and the HCP-1200, but the AX850 is still alive and kicking!

What would you use for a system like that? I have a brand new AX1200, a brand new HCP-1200 and a 2 weeks old AX850 with me right now that I can use. biggrin.gif
    
CPUCPUMotherboardGraphics
i7-3930k @ 5.1  i7-2600k @ 5.3 (2nd rig) Asus Rampage IV (X79) + Asus Maximus Extreme IV... 3X eVGA Titan Tri-SLI  
GraphicsRAMRAMHard Drive
2X Asus DirectCU II Top watercooled (2nd rig)  4X4GB=16GB Ripjaws DDR3 2400 CL9  4X4GB=16GB Ripjaws DDR3 1600 CL7 (2nd rig) Samsung 840 Evo 1TB SSD 
Hard DriveHard DriveHard DriveOptical Drive
Crucial M4 512Gb Crucial M4 256Gb  3XSeagate 2TB LG Blu-ray writer 
CoolingCoolingCoolingCooling
2X Quad-120 MCR420 2X Triple-120 MCR320 + 1X Triple-120 Feser 2X Dual-120 XSPC RX240 32 Gentle Typhoon fans (mix of 3000 and 1850rpm) 
CoolingCoolingOSMonitor
Reservoir 2X Koolance RP-452x2 with 4X MCP655 p... 2X EK Supreme HF CPU waterblock Windows 7 x64 Eyefinity: 3X ZR30W (30'')  
KeyboardPowerCaseMouse
Leopold Tenkeyless 1 Brown 3 Blue, Corsair K90 Antec HCP1200 + AX850 dual PSU main rig, AX120... Mountain Mods Extended Ascension + Pedestal 24 ... Corsair M60 + Razer DeathAdder  
Audio
PSB speakers 5.1 
  hide details  
Reply
    
CPUCPUMotherboardGraphics
i7-3930k @ 5.1  i7-2600k @ 5.3 (2nd rig) Asus Rampage IV (X79) + Asus Maximus Extreme IV... 3X eVGA Titan Tri-SLI  
GraphicsRAMRAMHard Drive
2X Asus DirectCU II Top watercooled (2nd rig)  4X4GB=16GB Ripjaws DDR3 2400 CL9  4X4GB=16GB Ripjaws DDR3 1600 CL7 (2nd rig) Samsung 840 Evo 1TB SSD 
Hard DriveHard DriveHard DriveOptical Drive
Crucial M4 512Gb Crucial M4 256Gb  3XSeagate 2TB LG Blu-ray writer 
CoolingCoolingCoolingCooling
2X Quad-120 MCR420 2X Triple-120 MCR320 + 1X Triple-120 Feser 2X Dual-120 XSPC RX240 32 Gentle Typhoon fans (mix of 3000 and 1850rpm) 
CoolingCoolingOSMonitor
Reservoir 2X Koolance RP-452x2 with 4X MCP655 p... 2X EK Supreme HF CPU waterblock Windows 7 x64 Eyefinity: 3X ZR30W (30'')  
KeyboardPowerCaseMouse
Leopold Tenkeyless 1 Brown 3 Blue, Corsair K90 Antec HCP1200 + AX850 dual PSU main rig, AX120... Mountain Mods Extended Ascension + Pedestal 24 ... Corsair M60 + Razer DeathAdder  
Audio
PSB speakers 5.1 
  hide details  
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Power Supplies
Overclock.net › Forums › Components › Power Supplies › FAQ: Dual Power Supplies