Overclock.net › Forums › Components › Power Supplies › How do amps come into play with a PSU?
New Posts  All Forums:Forum Nav:

How do amps come into play with a PSU?

post #1 of 17
Thread Starter 
Not quite sure about this one. So let's say my 560 ti takes 20A on the +12v rail. Do you multiply 20x12 = 240w? So a single 560 ti takes 240w? But the 560 ti's TDP is 170w. So how does that work exactly? And how does it change when it's single +12v rail vs multiple?
post #2 of 17
20A is a LOT of power, thats more than my entire sig rig running full throttle tongue.gif
no you take the amp draw times 120V from the wall, and multiply to get wattage
you take the Watts from the wall and divide by 120V to get amperage
you take amperage and multiply by wattage and you should get 120V

second part of your question:
when you have 1 rail on your PSU, that means ALL parts of your computer, drawing from +12V is coming from that 1 rail, which can be rated for lets say... 540W, now in a mutirail psu, certain +12V cables are attached to different rails, so you have to try your best as a builder to balance the load, which means not putting cable splitters all on one line and expecting that 1 out of say 3 +12V rails to power the full +12V capacity the PSU is rated for.
Edited by Pentium4 531 overclocker - 2/1/12 at 2:38pm
    
CPUMotherboardGraphicsRAM
Intel Core i7 3960X Extreme Edition Gigabyte GA-X79-UD3 MSI GTX 980 Gaming 4G HyperX Fury Red - 16GB DDR3 1866MHz 
RAMHard DriveHard DriveHard Drive
AMD Performance OEM - 16GB DDR3 1866MHz Sandisk Ultra II 500GB SSD Samsung 830 128GB SSD WD Caviar Black 500GB 
Hard DriveOptical DriveCoolingOS
WD Caviar Green 1TB MSI DVD Burner Corsair H100i Windows 10 Education 64Bit 
MonitorKeyboardPowerCase
Asus VE247H AZIO MGK L80 Mechanical Keyboard Corsair HX1050 NZXT Phantom 210 
MouseMouse PadAudioAudio
CM Sentinel Advance DXRacer Zero Series - White Shark Creative Sound Blaster Z Sennheiser HD 598Cs 
  hide details  
Reply
    
CPUMotherboardGraphicsRAM
Intel Core i7 3960X Extreme Edition Gigabyte GA-X79-UD3 MSI GTX 980 Gaming 4G HyperX Fury Red - 16GB DDR3 1866MHz 
RAMHard DriveHard DriveHard Drive
AMD Performance OEM - 16GB DDR3 1866MHz Sandisk Ultra II 500GB SSD Samsung 830 128GB SSD WD Caviar Black 500GB 
Hard DriveOptical DriveCoolingOS
WD Caviar Green 1TB MSI DVD Burner Corsair H100i Windows 10 Education 64Bit 
MonitorKeyboardPowerCase
Asus VE247H AZIO MGK L80 Mechanical Keyboard Corsair HX1050 NZXT Phantom 210 
MouseMouse PadAudioAudio
CM Sentinel Advance DXRacer Zero Series - White Shark Creative Sound Blaster Z Sennheiser HD 598Cs 
  hide details  
Reply
post #3 of 17
yes the simple way to calculate power is P = IV
where P is power in watts
I is current in amps
V is voltage in volts

TDP thermal design power is the amount of heat dissapted in watts thus the 560 ti dissipates up to 170W of heat..
Quote:
And how does it change when it's single +12v rail vs multiple?

not 100% sure on this smile.gif
Going to be chaep
(16 items)
 
Wife's Rig
(12 items)
 
 
CPUMotherboardGraphicsRAM
i7-3770k Gigabyte GA-Z77X-UP5 TH MSI GTX460 G.Skill TridentX 2400 2 x 4GB 
Hard DriveHard DriveOptical DriveCooling
Plextor M5p 128GB 2 x WD 500GB Blues LG Prolimatech Megahalems Rev C 
CoolingOSMonitorPower
Arctic F12 CO PWM x 2 Push/Pull Windows 7 64 bit Ultimate LG IPS235V Corsair AX850 
Case
Coolermaster HAF 912 advanced (Asia version) 
CPUMotherboardGraphicsRAM
I5-3570K Gigabyte Z68X-UD3H-B3 Inno3D Ichill GTX660 8GB G.Skill RipjawsX 1600 
Hard DriveHard DriveOptical DriveCooling
Samsung 830 128GB WD black 500GB Liteon Coolermaster Hyper 212+ EVO 
OSMonitorPowerCase
Win 7 ultimate Samsung Syncmaster 932gwe+ OCZ ZT series 550W Coolermaster 410 
CPUMotherboardRAMHard Drive
1.67Ghz Atom stock 1GB DDR2 2 x 500GB Western Digital Cavier Blacks [RAID 1] 
CoolingOSPowerCase
stock DSM3.2 [built on linux] stock stock 
OtherOther
Synology DX510 Expansion unit 5 x 1TB WD Cavier Blacks in a RAID 6 
  hide details  
Reply
Going to be chaep
(16 items)
 
Wife's Rig
(12 items)
 
 
CPUMotherboardGraphicsRAM
i7-3770k Gigabyte GA-Z77X-UP5 TH MSI GTX460 G.Skill TridentX 2400 2 x 4GB 
Hard DriveHard DriveOptical DriveCooling
Plextor M5p 128GB 2 x WD 500GB Blues LG Prolimatech Megahalems Rev C 
CoolingOSMonitorPower
Arctic F12 CO PWM x 2 Push/Pull Windows 7 64 bit Ultimate LG IPS235V Corsair AX850 
Case
Coolermaster HAF 912 advanced (Asia version) 
CPUMotherboardGraphicsRAM
I5-3570K Gigabyte Z68X-UD3H-B3 Inno3D Ichill GTX660 8GB G.Skill RipjawsX 1600 
Hard DriveHard DriveOptical DriveCooling
Samsung 830 128GB WD black 500GB Liteon Coolermaster Hyper 212+ EVO 
OSMonitorPowerCase
Win 7 ultimate Samsung Syncmaster 932gwe+ OCZ ZT series 550W Coolermaster 410 
CPUMotherboardRAMHard Drive
1.67Ghz Atom stock 1GB DDR2 2 x 500GB Western Digital Cavier Blacks [RAID 1] 
CoolingOSPowerCase
stock DSM3.2 [built on linux] stock stock 
OtherOther
Synology DX510 Expansion unit 5 x 1TB WD Cavier Blacks in a RAID 6 
  hide details  
Reply
post #4 of 17
Quote:
Originally Posted by Pentium4 531 overclocker View Post

20A is a LOT of power, thats more than my entire sig rig running full throttle tongue.gif
no you take the amp draw times 120V from the wall, and multiply to get wattage
you take the 120V from the wall and divide by wattage to get amperage
you take amperage and multiply by wattage and you should get 120V
second part of your question:
when you have 1 rail on your PSU, that means ALL parts of your computer, drawing from +12V is coming from that 1 rail, which can be rated for lets say... 540W, now in a mutirail psu, certain +12V cables are attached to different rails, so you have to try your best as a builder to balance the load, which means not putting cable splitters all on one line and expecting that 1 out of say 3 +12V rails to power the full +12V capacity the PSU is rated for.

i dont know about that, ive always thought of it as the voltage of the rail multiplied by the amperage to get watts. i know the grid voltage is applied vs the amperage in the transient stage, but then gets rectified and transformed to suit whatever rail needs the power. at least, thats what i imagined the 20A referred to, cant see why a card would rate their required amperage based on the grid, especially since some grids are 115, 120, 230, 240 etc etc
Edited by Vuashke - 1/28/12 at 10:30pm
post #5 of 17
Thread Starter 
Quote:
Originally Posted by stubass View Post

yes the simple way to calculate power is P = IV
where P is power in watts
I is current in amps
V is voltage in volts
TDP thermal design power is the amount of heat dissapted in watts thus the 560 ti dissipates up to 170W of heat..
not 100% sure on this smile.gif

So what happens if you exceed 170w? 560 ti explodes? lol
post #6 of 17
Quote:
Originally Posted by venomblade View Post

So what happens if you exceed 170w? 560 ti explodes? lol

No, PSUs don't work that way. 170w is a conservative estimate of what a 560 ti draws at load. I would imagine it draws more like 140w at load. And the amp rating on your PSU is the max of what it's capable of outputting. Usually. Cheaper power supplies often straight-up lie about what they can provide.
Clasicos
(16 items)
 
Proletariatop
(13 items)
 
Upgrayedds
(4 items)
 
CPUMotherboardGraphicsGraphics
Phenom II X6 1090T 4.1ghz|1.60v GA-MA790X-UD4P Sapphire 6870|1GhzCore 1.27GhzMem nVidia Quadro NVS 290 
GraphicsRAMHard DriveOptical Drive
Sapphire 6870|1GhzCore 1.27GhzMem 2x2GB Geil 800 + 2x2GB Micron 800 2x Hitachi 500 GB RAID1 + 870 GB JBOD Optiarc DVD-RAM 
OSMonitorKeyboardPower
Windows 7 Ultimate x64 1x Hanns·G 28" + 2x AOC 20" + 1x Envision 19" Unicomp Customizer Corsair GS600 
CaseMouseMouse PadAudio
Xigmatek Utgard Logitech MX518 Waxed wooden surface. XFi XtremeGamer 
CPUMotherboardGraphicsRAM
AMD Fusion E-240 @ 1.5Ghz Hudson D1 Chipset AMD Radeon 6310 2x4GB DDR3 1333 
Hard DriveOSMonitorPower
Crucial M4 64GB Ubuntu 12.04 w/LXDE 11.6" 1366x768 3-cell lithium ion 
Case
ThinkPad X Series X120e 
CPUGraphicsGraphicsPower
AMD 1090T AMD 6870 AMD 6870 Thermaltake Toughpower XT TPX-775M 775W PSU 
  hide details  
Reply
Clasicos
(16 items)
 
Proletariatop
(13 items)
 
Upgrayedds
(4 items)
 
CPUMotherboardGraphicsGraphics
Phenom II X6 1090T 4.1ghz|1.60v GA-MA790X-UD4P Sapphire 6870|1GhzCore 1.27GhzMem nVidia Quadro NVS 290 
GraphicsRAMHard DriveOptical Drive
Sapphire 6870|1GhzCore 1.27GhzMem 2x2GB Geil 800 + 2x2GB Micron 800 2x Hitachi 500 GB RAID1 + 870 GB JBOD Optiarc DVD-RAM 
OSMonitorKeyboardPower
Windows 7 Ultimate x64 1x Hanns·G 28" + 2x AOC 20" + 1x Envision 19" Unicomp Customizer Corsair GS600 
CaseMouseMouse PadAudio
Xigmatek Utgard Logitech MX518 Waxed wooden surface. XFi XtremeGamer 
CPUMotherboardGraphicsRAM
AMD Fusion E-240 @ 1.5Ghz Hudson D1 Chipset AMD Radeon 6310 2x4GB DDR3 1333 
Hard DriveOSMonitorPower
Crucial M4 64GB Ubuntu 12.04 w/LXDE 11.6" 1366x768 3-cell lithium ion 
Case
ThinkPad X Series X120e 
CPUGraphicsGraphicsPower
AMD 1090T AMD 6870 AMD 6870 Thermaltake Toughpower XT TPX-775M 775W PSU 
  hide details  
Reply
post #7 of 17
Quote:
Originally Posted by venomblade View Post

So what happens if you exceed 170w? 560 ti explodes? lol

Hopefully your rig would shut down but its always possible to burn things up. But most likely you're not getting close to 170w on a 560Ti, at least I wouldn't think so.
post #8 of 17
Quote:
Originally Posted by Vuashke View Post

i dont know about that, ive always thought of it as the voltage of the rail multiplied by the amperage to get watts. i know the grid voltage is applied vs the amperage in the transient stage, but then gets rectified and transformed to suit whatever rail needs the power. at least, thats what i imagined the 20A referred to, cant see why a card would rate their required amperage based on the grid, especially since some grids are 115, 120, 230, 240 etc etc

no.... i think your confused somewhere...
Quote:
Originally Posted by venomblade View Post

So what happens if you exceed 170w? 560 ti explodes? lol
power supplies do not push power, PC parts pull power, if you stuck a 1000W power supply in a system that draws 200W, the power supply is only going to output 200W and no more, now if the graphics card pulled too much power for the PSU, then more then likely, the PSU will explode biggrin.gif
Edited by Pentium4 531 overclocker - 1/28/12 at 10:39pm
    
CPUMotherboardGraphicsRAM
Intel Core i7 3960X Extreme Edition Gigabyte GA-X79-UD3 MSI GTX 980 Gaming 4G HyperX Fury Red - 16GB DDR3 1866MHz 
RAMHard DriveHard DriveHard Drive
AMD Performance OEM - 16GB DDR3 1866MHz Sandisk Ultra II 500GB SSD Samsung 830 128GB SSD WD Caviar Black 500GB 
Hard DriveOptical DriveCoolingOS
WD Caviar Green 1TB MSI DVD Burner Corsair H100i Windows 10 Education 64Bit 
MonitorKeyboardPowerCase
Asus VE247H AZIO MGK L80 Mechanical Keyboard Corsair HX1050 NZXT Phantom 210 
MouseMouse PadAudioAudio
CM Sentinel Advance DXRacer Zero Series - White Shark Creative Sound Blaster Z Sennheiser HD 598Cs 
  hide details  
Reply
    
CPUMotherboardGraphicsRAM
Intel Core i7 3960X Extreme Edition Gigabyte GA-X79-UD3 MSI GTX 980 Gaming 4G HyperX Fury Red - 16GB DDR3 1866MHz 
RAMHard DriveHard DriveHard Drive
AMD Performance OEM - 16GB DDR3 1866MHz Sandisk Ultra II 500GB SSD Samsung 830 128GB SSD WD Caviar Black 500GB 
Hard DriveOptical DriveCoolingOS
WD Caviar Green 1TB MSI DVD Burner Corsair H100i Windows 10 Education 64Bit 
MonitorKeyboardPowerCase
Asus VE247H AZIO MGK L80 Mechanical Keyboard Corsair HX1050 NZXT Phantom 210 
MouseMouse PadAudioAudio
CM Sentinel Advance DXRacer Zero Series - White Shark Creative Sound Blaster Z Sennheiser HD 598Cs 
  hide details  
Reply
post #9 of 17
Quote:
Originally Posted by Pentium4 531 overclocker View Post

no.... i think your confused somewhere...

i dunno dude, i think its pretty clear that the wattage of this card isnt measured by the voltage of the grid

http://www.xbitlabs.com/articles/graphics/display/geforce-gtx-560-ti_4.html#sect0

i know what you are saying about the 115v pulled from the grid in the filtering stage, i guess its just confusing since the title seems to be about amps coming into the psu whereas the actual post talks about amperage outputted from the psu
post #10 of 17
Quote:
Originally Posted by venomblade View Post

So what happens if you exceed 170w? 560 ti explodes? lol

nah not quite lol

i beleive TDP is primarily used as a guideline for manufacturers of thermal solutions (heatsinks/fans, etc) which tells them how much heat their solution should dissipate. well atleast for CPUs, i assumiong GPUs work the same way smile.gif
Going to be chaep
(16 items)
 
Wife's Rig
(12 items)
 
 
CPUMotherboardGraphicsRAM
i7-3770k Gigabyte GA-Z77X-UP5 TH MSI GTX460 G.Skill TridentX 2400 2 x 4GB 
Hard DriveHard DriveOptical DriveCooling
Plextor M5p 128GB 2 x WD 500GB Blues LG Prolimatech Megahalems Rev C 
CoolingOSMonitorPower
Arctic F12 CO PWM x 2 Push/Pull Windows 7 64 bit Ultimate LG IPS235V Corsair AX850 
Case
Coolermaster HAF 912 advanced (Asia version) 
CPUMotherboardGraphicsRAM
I5-3570K Gigabyte Z68X-UD3H-B3 Inno3D Ichill GTX660 8GB G.Skill RipjawsX 1600 
Hard DriveHard DriveOptical DriveCooling
Samsung 830 128GB WD black 500GB Liteon Coolermaster Hyper 212+ EVO 
OSMonitorPowerCase
Win 7 ultimate Samsung Syncmaster 932gwe+ OCZ ZT series 550W Coolermaster 410 
CPUMotherboardRAMHard Drive
1.67Ghz Atom stock 1GB DDR2 2 x 500GB Western Digital Cavier Blacks [RAID 1] 
CoolingOSPowerCase
stock DSM3.2 [built on linux] stock stock 
OtherOther
Synology DX510 Expansion unit 5 x 1TB WD Cavier Blacks in a RAID 6 
  hide details  
Reply
Going to be chaep
(16 items)
 
Wife's Rig
(12 items)
 
 
CPUMotherboardGraphicsRAM
i7-3770k Gigabyte GA-Z77X-UP5 TH MSI GTX460 G.Skill TridentX 2400 2 x 4GB 
Hard DriveHard DriveOptical DriveCooling
Plextor M5p 128GB 2 x WD 500GB Blues LG Prolimatech Megahalems Rev C 
CoolingOSMonitorPower
Arctic F12 CO PWM x 2 Push/Pull Windows 7 64 bit Ultimate LG IPS235V Corsair AX850 
Case
Coolermaster HAF 912 advanced (Asia version) 
CPUMotherboardGraphicsRAM
I5-3570K Gigabyte Z68X-UD3H-B3 Inno3D Ichill GTX660 8GB G.Skill RipjawsX 1600 
Hard DriveHard DriveOptical DriveCooling
Samsung 830 128GB WD black 500GB Liteon Coolermaster Hyper 212+ EVO 
OSMonitorPowerCase
Win 7 ultimate Samsung Syncmaster 932gwe+ OCZ ZT series 550W Coolermaster 410 
CPUMotherboardRAMHard Drive
1.67Ghz Atom stock 1GB DDR2 2 x 500GB Western Digital Cavier Blacks [RAID 1] 
CoolingOSPowerCase
stock DSM3.2 [built on linux] stock stock 
OtherOther
Synology DX510 Expansion unit 5 x 1TB WD Cavier Blacks in a RAID 6 
  hide details  
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Power Supplies
Overclock.net › Forums › Components › Power Supplies › How do amps come into play with a PSU?