Overclock.net › Forums › Components › Power Supplies › Question about PSU
New Posts  All Forums:Forum Nav:

Question about PSU

post #1 of 14
Thread Starter 
My question is that, is the amount of wattage the PSU pulls out of the wall equal to the PSU's wattage or equal to your system's wattage?

Eg.) You run a 1000W PSU but your system only need 500. So does the PSU pull 500W or 1000W out of the wall?

**IGNORING EFFICIENCIES FOR SIMPLEST SITUATION
Incomplete
(16 items)
 
  
CPUMotherboardGraphicsRAM
i5 2400 p8h67m-le asus 560ti dcu ii top ripjaws 2x2gb 
Hard DriveOptical DriveCoolingOS
wd black 500gb asus 24x corsair a70 win7 pro 
MonitorKeyboardPowerCase
ve278q azio levetron kb577u antec tp-650 haf 912 
MouseMouse PadAudioAudio
logitech g9x steelseries xxl logitech z313 corsair hs1a 
  hide details  
Reply
Incomplete
(16 items)
 
  
CPUMotherboardGraphicsRAM
i5 2400 p8h67m-le asus 560ti dcu ii top ripjaws 2x2gb 
Hard DriveOptical DriveCoolingOS
wd black 500gb asus 24x corsair a70 win7 pro 
MonitorKeyboardPowerCase
ve278q azio levetron kb577u antec tp-650 haf 912 
MouseMouse PadAudioAudio
logitech g9x steelseries xxl logitech z313 corsair hs1a 
  hide details  
Reply
post #2 of 14
Quote:
Originally Posted by reyo View Post
This seems like a more technical question I'm not sure about. My question is that, is the amount of wattage the PSU pulls out of the wall equal to the PSU's wattage or equal to your system's wattage?

Example) You run a 1000W PSU but your system only need 500. So does the PSU pull 500W or 1000W out of the wall?
If your system draws 500w under load out of a 1000w psu, then the draw from the wall will equal whatever 500w is about 80% of depending on the efficiency.

Draw from wall * efficiency = power the pc is drawing.

PSU's are most efficient at 50% load.
The Butthurt Box
(21 items)
 
   
CPUMotherboardGraphicsGraphics
Intel Core i5 2500K P67 Professional AMD Radeon HD 6950 unlock NVIDIA GeForce GTX 460 2gb 
RAMRAMHard DriveHard Drive
G.Skill Ripjaws G.Skill Ripjaws Intel X25-V Seagate Barracuda 
Hard DriveOptical DriveOSMonitor
WD Goflex USB 3.0 24x DVD R/W DL Win7 Ultermate 64 Acer 20in 1600x900 
MonitorMonitorMonitorKeyboard
Compaq 20in 1600x900 17in Dell 1280x1024 19in Gateway 1280x1024 Razer Blackwidow mech w/ cherry MX blues 
PowerCaseMouseAudio
Kingwin LZ-750 HAF 932 + sound activated lights Logitech G500 Rosewill USB headset 
CPUMotherboardGraphicsRAM
Pentium 4 3.2ghz w/ HT HP Intel IGP 4gb Mushkin DDR2 
Hard DriveOSPowerCase
80gb sata WinXP Pro HP OEM HP Small form factor 
  hide details  
Reply
The Butthurt Box
(21 items)
 
   
CPUMotherboardGraphicsGraphics
Intel Core i5 2500K P67 Professional AMD Radeon HD 6950 unlock NVIDIA GeForce GTX 460 2gb 
RAMRAMHard DriveHard Drive
G.Skill Ripjaws G.Skill Ripjaws Intel X25-V Seagate Barracuda 
Hard DriveOptical DriveOSMonitor
WD Goflex USB 3.0 24x DVD R/W DL Win7 Ultermate 64 Acer 20in 1600x900 
MonitorMonitorMonitorKeyboard
Compaq 20in 1600x900 17in Dell 1280x1024 19in Gateway 1280x1024 Razer Blackwidow mech w/ cherry MX blues 
PowerCaseMouseAudio
Kingwin LZ-750 HAF 932 + sound activated lights Logitech G500 Rosewill USB headset 
CPUMotherboardGraphicsRAM
Pentium 4 3.2ghz w/ HT HP Intel IGP 4gb Mushkin DDR2 
Hard DriveOSPowerCase
80gb sata WinXP Pro HP OEM HP Small form factor 
  hide details  
Reply
post #3 of 14
Quote:
Originally Posted by railfan844 View Post
If your system draws 500w under load out of a 1000w psu, then the draw from the wall will equal whatever 500w is about 80% of depending on the efficiency.

Draw from wall * efficiency = power the pc is drawing.

PSU's are most efficient at 50% load.
Depends solely on the PSU.
    
CPUMotherboardGraphicsRAM
Xeon w3680 Gigabyte X58A-UD3R GTX 295 Engineering Samples 2X Corsair XMS3 
Hard DriveHard DriveCoolingOS
Sandisk SSD Seagate Corsair H50 W7 Ult 
MonitorMonitorKeyboardCase
Viewsonic VA1912wb Viewsonic VA912b K350 CM HAF 
Mouse
Logitech M570 
  hide details  
Reply
    
CPUMotherboardGraphicsRAM
Xeon w3680 Gigabyte X58A-UD3R GTX 295 Engineering Samples 2X Corsair XMS3 
Hard DriveHard DriveCoolingOS
Sandisk SSD Seagate Corsair H50 W7 Ult 
MonitorMonitorKeyboardCase
Viewsonic VA1912wb Viewsonic VA912b K350 CM HAF 
Mouse
Logitech M570 
  hide details  
Reply
post #4 of 14
Edit: just saw your edit.

A 1000w psu can provide UP TO 1000w, it will not always draw 1000w from the wall.
The Butthurt Box
(21 items)
 
   
CPUMotherboardGraphicsGraphics
Intel Core i5 2500K P67 Professional AMD Radeon HD 6950 unlock NVIDIA GeForce GTX 460 2gb 
RAMRAMHard DriveHard Drive
G.Skill Ripjaws G.Skill Ripjaws Intel X25-V Seagate Barracuda 
Hard DriveOptical DriveOSMonitor
WD Goflex USB 3.0 24x DVD R/W DL Win7 Ultermate 64 Acer 20in 1600x900 
MonitorMonitorMonitorKeyboard
Compaq 20in 1600x900 17in Dell 1280x1024 19in Gateway 1280x1024 Razer Blackwidow mech w/ cherry MX blues 
PowerCaseMouseAudio
Kingwin LZ-750 HAF 932 + sound activated lights Logitech G500 Rosewill USB headset 
CPUMotherboardGraphicsRAM
Pentium 4 3.2ghz w/ HT HP Intel IGP 4gb Mushkin DDR2 
Hard DriveOSPowerCase
80gb sata WinXP Pro HP OEM HP Small form factor 
  hide details  
Reply
The Butthurt Box
(21 items)
 
   
CPUMotherboardGraphicsGraphics
Intel Core i5 2500K P67 Professional AMD Radeon HD 6950 unlock NVIDIA GeForce GTX 460 2gb 
RAMRAMHard DriveHard Drive
G.Skill Ripjaws G.Skill Ripjaws Intel X25-V Seagate Barracuda 
Hard DriveOptical DriveOSMonitor
WD Goflex USB 3.0 24x DVD R/W DL Win7 Ultermate 64 Acer 20in 1600x900 
MonitorMonitorMonitorKeyboard
Compaq 20in 1600x900 17in Dell 1280x1024 19in Gateway 1280x1024 Razer Blackwidow mech w/ cherry MX blues 
PowerCaseMouseAudio
Kingwin LZ-750 HAF 932 + sound activated lights Logitech G500 Rosewill USB headset 
CPUMotherboardGraphicsRAM
Pentium 4 3.2ghz w/ HT HP Intel IGP 4gb Mushkin DDR2 
Hard DriveOSPowerCase
80gb sata WinXP Pro HP OEM HP Small form factor 
  hide details  
Reply
post #5 of 14
Quote:
Originally Posted by railfan844 View Post
Draw from wall * efficiency = power the pc is drawing.
So a useable equation for what OP is trying to find out is
Power of PC/Efficiency = Draw from wall
for power of PC you can make a general estimation
    
CPUMotherboardGraphicsRAM
i5 2500K [Asus] P8P67 Pro [EVGA] 1050 Ti [Crucial] Ballistix Tactical 
Hard DriveHard DriveCoolingOS
[Crucial] M4 128gb [WD] Cavier Black [Noctua] NH-D14 Windows 7 Home Premium 
MonitorMonitorKeyboardPower
[Asus] VG236 23 inch 120 Hz [HP]w2007 (Offset) [Logitech] G15 [Corsair] HX 750 
CaseMouseAudio
[Silverstone] RV02 [Logitech] G5 [Superlux] HD668B 
  hide details  
Reply
    
CPUMotherboardGraphicsRAM
i5 2500K [Asus] P8P67 Pro [EVGA] 1050 Ti [Crucial] Ballistix Tactical 
Hard DriveHard DriveCoolingOS
[Crucial] M4 128gb [WD] Cavier Black [Noctua] NH-D14 Windows 7 Home Premium 
MonitorMonitorKeyboardPower
[Asus] VG236 23 inch 120 Hz [HP]w2007 (Offset) [Logitech] G15 [Corsair] HX 750 
CaseMouseAudio
[Silverstone] RV02 [Logitech] G5 [Superlux] HD668B 
  hide details  
Reply
post #6 of 14
Quote:
Originally Posted by MR KROGOTH View Post
Depends solely on the PSU.
Hmm I thought that it was like this for all transformers, etc?

Let me dig out my old CPU mag collection and I'll get back to you on that
The Butthurt Box
(21 items)
 
   
CPUMotherboardGraphicsGraphics
Intel Core i5 2500K P67 Professional AMD Radeon HD 6950 unlock NVIDIA GeForce GTX 460 2gb 
RAMRAMHard DriveHard Drive
G.Skill Ripjaws G.Skill Ripjaws Intel X25-V Seagate Barracuda 
Hard DriveOptical DriveOSMonitor
WD Goflex USB 3.0 24x DVD R/W DL Win7 Ultermate 64 Acer 20in 1600x900 
MonitorMonitorMonitorKeyboard
Compaq 20in 1600x900 17in Dell 1280x1024 19in Gateway 1280x1024 Razer Blackwidow mech w/ cherry MX blues 
PowerCaseMouseAudio
Kingwin LZ-750 HAF 932 + sound activated lights Logitech G500 Rosewill USB headset 
CPUMotherboardGraphicsRAM
Pentium 4 3.2ghz w/ HT HP Intel IGP 4gb Mushkin DDR2 
Hard DriveOSPowerCase
80gb sata WinXP Pro HP OEM HP Small form factor 
  hide details  
Reply
The Butthurt Box
(21 items)
 
   
CPUMotherboardGraphicsGraphics
Intel Core i5 2500K P67 Professional AMD Radeon HD 6950 unlock NVIDIA GeForce GTX 460 2gb 
RAMRAMHard DriveHard Drive
G.Skill Ripjaws G.Skill Ripjaws Intel X25-V Seagate Barracuda 
Hard DriveOptical DriveOSMonitor
WD Goflex USB 3.0 24x DVD R/W DL Win7 Ultermate 64 Acer 20in 1600x900 
MonitorMonitorMonitorKeyboard
Compaq 20in 1600x900 17in Dell 1280x1024 19in Gateway 1280x1024 Razer Blackwidow mech w/ cherry MX blues 
PowerCaseMouseAudio
Kingwin LZ-750 HAF 932 + sound activated lights Logitech G500 Rosewill USB headset 
CPUMotherboardGraphicsRAM
Pentium 4 3.2ghz w/ HT HP Intel IGP 4gb Mushkin DDR2 
Hard DriveOSPowerCase
80gb sata WinXP Pro HP OEM HP Small form factor 
  hide details  
Reply
post #7 of 14
Quote:
Originally Posted by railfan844 View Post
Hmm I thought that it was like this for all transformers, etc?

Let me dig out my old CPU mag collection and I'll get back to you on that
Maybe with older stuff. Technology advances.
Nicer units can output more than their stickers say they can and remain efficient.
    
CPUMotherboardGraphicsRAM
Xeon w3680 Gigabyte X58A-UD3R GTX 295 Engineering Samples 2X Corsair XMS3 
Hard DriveHard DriveCoolingOS
Sandisk SSD Seagate Corsair H50 W7 Ult 
MonitorMonitorKeyboardCase
Viewsonic VA1912wb Viewsonic VA912b K350 CM HAF 
Mouse
Logitech M570 
  hide details  
Reply
    
CPUMotherboardGraphicsRAM
Xeon w3680 Gigabyte X58A-UD3R GTX 295 Engineering Samples 2X Corsair XMS3 
Hard DriveHard DriveCoolingOS
Sandisk SSD Seagate Corsair H50 W7 Ult 
MonitorMonitorKeyboardCase
Viewsonic VA1912wb Viewsonic VA912b K350 CM HAF 
Mouse
Logitech M570 
  hide details  
Reply
post #8 of 14
Quote:
Originally Posted by railfan844 View Post
If your system draws 500w under load out of a 1000w psu, then the draw from the wall will equal whatever 500w is about 80% of depending on the efficiency.

Draw from wall * efficiency = power the pc is drawing.

PSU's are most efficient at 50% load.
1) You are correct. If the system draw is 500w from the PSU, then you use math with that and the efficiency to determine wattage from the wall.

2) 500 (power draw) / 0.8 (efficiency) = 625w from the wall.
625 (power from the wall) x 0.8 (efficiency) = 500w draw from the components.

3) PSU's ARE NOT most efficient at 50% load. Get that myth stopped right now. Please see here for more details.
Junkyard
(18 items)
 
NAStradamous
(12 items)
 
HTPC01
(16 items)
 
CPUMotherboardGraphicsRAM
Intel i5 2320 @ 3.1GHz MSI B75MA-E33 HIS HD7970 3GB @ 1050 / 1700, 1.17v Patriot 2x4GB DDR3-1066 
Hard DriveHard DriveOptical DriveCooling
Crucial MX100 256GB WD Green 2TB DVDRW Corsair H50 Push / Pull 
CoolingOSMonitorMonitor
NZXT 120mm fans strapped to stock 7970 cooler Windows 10 Pro Dell 3007WFP Dell 2007FP 
MonitorKeyboardPowerCase
Dell 2007FP Cheap Toshiba (R.I.P. Ducky) PC Power & Cooling Silencer MKIII 950w Cheap Garbage (free) 
MouseAudio
Logitech G602 Yardsale Special 
CPUMotherboardGraphicsRAM
Intel Core i5 3330 Asus H61 MSI GTX 750Ti Low Profile 2x4GB Hynix DDR3-1333 
Hard DriveHard DriveOptical DriveCooling
60GB Kingston SSD 1TB Seagate Samsung DVDRW CoolerMaster Gemin II 
OSMonitorKeyboardPower
Windows 8.1 + Steam Big Picture / Plex HT 50" Insignia LED 1080p Logitech Rosewill Green 530w 
CaseMouseAudioOther
Silverstone HTPC Logitech Pioneer 2.0 tower speakers + 135w RMS Rosewill MCE Remote 
  hide details  
Reply
Junkyard
(18 items)
 
NAStradamous
(12 items)
 
HTPC01
(16 items)
 
CPUMotherboardGraphicsRAM
Intel i5 2320 @ 3.1GHz MSI B75MA-E33 HIS HD7970 3GB @ 1050 / 1700, 1.17v Patriot 2x4GB DDR3-1066 
Hard DriveHard DriveOptical DriveCooling
Crucial MX100 256GB WD Green 2TB DVDRW Corsair H50 Push / Pull 
CoolingOSMonitorMonitor
NZXT 120mm fans strapped to stock 7970 cooler Windows 10 Pro Dell 3007WFP Dell 2007FP 
MonitorKeyboardPowerCase
Dell 2007FP Cheap Toshiba (R.I.P. Ducky) PC Power & Cooling Silencer MKIII 950w Cheap Garbage (free) 
MouseAudio
Logitech G602 Yardsale Special 
CPUMotherboardGraphicsRAM
Intel Core i5 3330 Asus H61 MSI GTX 750Ti Low Profile 2x4GB Hynix DDR3-1333 
Hard DriveHard DriveOptical DriveCooling
60GB Kingston SSD 1TB Seagate Samsung DVDRW CoolerMaster Gemin II 
OSMonitorKeyboardPower
Windows 8.1 + Steam Big Picture / Plex HT 50" Insignia LED 1080p Logitech Rosewill Green 530w 
CaseMouseAudioOther
Silverstone HTPC Logitech Pioneer 2.0 tower speakers + 135w RMS Rosewill MCE Remote 
  hide details  
Reply
post #9 of 14
Quote:
Originally Posted by MR KROGOTH View Post
Maybe with older stuff. Technology advances.
Nicer units can output more than their stickers say they can and remain efficient.
I didn't mean that most psu's are most efficient at about 50%, I thought this was a rule of electricity. Converting from one form to another is most efficient at 50%, or so I thought.....

My recollection of that article I read may just be warped, I'm looking for the magazine right now.
The Butthurt Box
(21 items)
 
   
CPUMotherboardGraphicsGraphics
Intel Core i5 2500K P67 Professional AMD Radeon HD 6950 unlock NVIDIA GeForce GTX 460 2gb 
RAMRAMHard DriveHard Drive
G.Skill Ripjaws G.Skill Ripjaws Intel X25-V Seagate Barracuda 
Hard DriveOptical DriveOSMonitor
WD Goflex USB 3.0 24x DVD R/W DL Win7 Ultermate 64 Acer 20in 1600x900 
MonitorMonitorMonitorKeyboard
Compaq 20in 1600x900 17in Dell 1280x1024 19in Gateway 1280x1024 Razer Blackwidow mech w/ cherry MX blues 
PowerCaseMouseAudio
Kingwin LZ-750 HAF 932 + sound activated lights Logitech G500 Rosewill USB headset 
CPUMotherboardGraphicsRAM
Pentium 4 3.2ghz w/ HT HP Intel IGP 4gb Mushkin DDR2 
Hard DriveOSPowerCase
80gb sata WinXP Pro HP OEM HP Small form factor 
  hide details  
Reply
The Butthurt Box
(21 items)
 
   
CPUMotherboardGraphicsGraphics
Intel Core i5 2500K P67 Professional AMD Radeon HD 6950 unlock NVIDIA GeForce GTX 460 2gb 
RAMRAMHard DriveHard Drive
G.Skill Ripjaws G.Skill Ripjaws Intel X25-V Seagate Barracuda 
Hard DriveOptical DriveOSMonitor
WD Goflex USB 3.0 24x DVD R/W DL Win7 Ultermate 64 Acer 20in 1600x900 
MonitorMonitorMonitorKeyboard
Compaq 20in 1600x900 17in Dell 1280x1024 19in Gateway 1280x1024 Razer Blackwidow mech w/ cherry MX blues 
PowerCaseMouseAudio
Kingwin LZ-750 HAF 932 + sound activated lights Logitech G500 Rosewill USB headset 
CPUMotherboardGraphicsRAM
Pentium 4 3.2ghz w/ HT HP Intel IGP 4gb Mushkin DDR2 
Hard DriveOSPowerCase
80gb sata WinXP Pro HP OEM HP Small form factor 
  hide details  
Reply
post #10 of 14
Quote:
Originally Posted by railfan844 View Post
I didn't mean that most psu's are most efficient at about 50%, I thought this was a rule of electricity. Converting from one form to another is most efficient at 50%, or so I thought.....

My recollection of that article I read may just be warped, I'm looking for the magazine right now.
It's clearly warped, see the article I linked above. The 50% load thing is a complete myth, and its been busted time and time again.
Junkyard
(18 items)
 
NAStradamous
(12 items)
 
HTPC01
(16 items)
 
CPUMotherboardGraphicsRAM
Intel i5 2320 @ 3.1GHz MSI B75MA-E33 HIS HD7970 3GB @ 1050 / 1700, 1.17v Patriot 2x4GB DDR3-1066 
Hard DriveHard DriveOptical DriveCooling
Crucial MX100 256GB WD Green 2TB DVDRW Corsair H50 Push / Pull 
CoolingOSMonitorMonitor
NZXT 120mm fans strapped to stock 7970 cooler Windows 10 Pro Dell 3007WFP Dell 2007FP 
MonitorKeyboardPowerCase
Dell 2007FP Cheap Toshiba (R.I.P. Ducky) PC Power & Cooling Silencer MKIII 950w Cheap Garbage (free) 
MouseAudio
Logitech G602 Yardsale Special 
CPUMotherboardGraphicsRAM
Intel Core i5 3330 Asus H61 MSI GTX 750Ti Low Profile 2x4GB Hynix DDR3-1333 
Hard DriveHard DriveOptical DriveCooling
60GB Kingston SSD 1TB Seagate Samsung DVDRW CoolerMaster Gemin II 
OSMonitorKeyboardPower
Windows 8.1 + Steam Big Picture / Plex HT 50" Insignia LED 1080p Logitech Rosewill Green 530w 
CaseMouseAudioOther
Silverstone HTPC Logitech Pioneer 2.0 tower speakers + 135w RMS Rosewill MCE Remote 
  hide details  
Reply
Junkyard
(18 items)
 
NAStradamous
(12 items)
 
HTPC01
(16 items)
 
CPUMotherboardGraphicsRAM
Intel i5 2320 @ 3.1GHz MSI B75MA-E33 HIS HD7970 3GB @ 1050 / 1700, 1.17v Patriot 2x4GB DDR3-1066 
Hard DriveHard DriveOptical DriveCooling
Crucial MX100 256GB WD Green 2TB DVDRW Corsair H50 Push / Pull 
CoolingOSMonitorMonitor
NZXT 120mm fans strapped to stock 7970 cooler Windows 10 Pro Dell 3007WFP Dell 2007FP 
MonitorKeyboardPowerCase
Dell 2007FP Cheap Toshiba (R.I.P. Ducky) PC Power & Cooling Silencer MKIII 950w Cheap Garbage (free) 
MouseAudio
Logitech G602 Yardsale Special 
CPUMotherboardGraphicsRAM
Intel Core i5 3330 Asus H61 MSI GTX 750Ti Low Profile 2x4GB Hynix DDR3-1333 
Hard DriveHard DriveOptical DriveCooling
60GB Kingston SSD 1TB Seagate Samsung DVDRW CoolerMaster Gemin II 
OSMonitorKeyboardPower
Windows 8.1 + Steam Big Picture / Plex HT 50" Insignia LED 1080p Logitech Rosewill Green 530w 
CaseMouseAudioOther
Silverstone HTPC Logitech Pioneer 2.0 tower speakers + 135w RMS Rosewill MCE Remote 
  hide details  
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Power Supplies
Overclock.net › Forums › Components › Power Supplies › Question about PSU