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power calculations

post #1 of 16
Thread Starter 
i have been wondering lately, because i learned a little more, and because i have always done this, how is a power supply calculated if you just know the gpu, and how many gpus? i have always done it like this:

what the gpu draws from the wall-~10
+100 to 150 for the cpu(to my knowledge that is far more than it needs)
+100 for the rest of the system(again i have thought that this is overkill)

and i read these reviews that give 350 to the rest of the system instead of 250, just wondering how everyone else does it...

note: i am pretty sure this method works
post #2 of 16
A modern system draws most of its power from the +12V, and of course the biggest consumer is the graphics card while the CPU is 2nd in line.

So I take the manufacturer's recommended power supply wattage, and I subtract about 50W since quality power supplies that we recommend are continuous, not peak-rated.

So if I see someone with an i7-920 and they want to upgrade from a GTX 460 to a GTX 580 with something like the Corsair's VX450, then I'll tell them to at least get something like the 550W TruePower New (at the very least). If they have a system like mine, then I just recommend a quality 550W unit without worrying about it.
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post #3 of 16
Thread Starter 
Quote:
Originally Posted by TwoCables View Post
A modern system draws most of its power from the +12V, and of course the biggest consumer is the graphics card while the CPU is 2nd in line.

So I take the manufacturer's recommended power supply wattage, and I subtract about 50W since quality power supplies that we recommend are continuous, not peak-rated.

So if I see someone with an i7-920 and they want to upgrade from a GTX 460 to a GTX 580 with something like the Corsair's VX450, then I'll tell them to at least get something like the 550W TruePower New (at the very least). If they have a system like mine, then I just recommend a quality 550W unit without worrying about it.
yep..... going by my method it would come up to 490w for 1 580, and i would say 550 or 500
post #4 of 16
I like to use Newegg's online calcuator. Try your method against the one on Newegg, see how they compare. I usually round up to a effecient good quality PS from the reccomedation.
    
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post #5 of 16
Did they change the Newegg calculator? Or did they just pretend it wasn't vastly inflating results?
Urm... nope... the Egg still says I need nearly 800w, when I know for certain I could run this thing on a 650w unit with the right connectors...
If you're buying a top end unit, just ask around here, these calculators are designed around the PSU makers WHICH LIE and inflate their ratings massively.
Hopefully, when Nvidia and ATi shift their recommendations to only using 80+ PSUs then things may become more accurate.
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post #6 of 16
Thread Starter 
well.... i was expecting replies..... i guess i am disappointed..... i find this stuff interesting.... and fun..... oh well, i will stick to what i have been doing...
post #7 of 16
Quote:
Originally Posted by Cvalley75 View Post
I like to use Newegg's online calcuator. Try your method against the one on Newegg, see how they compare. I usually round up to a effecient good quality PS from the reccomedation.
That is actually one of the worst online PSU calculators on the internet. No OCN member should be using a PSU calculator, but if you must use one then use this one:

http://extreme.outervision.com/psucalculatorlite.jsp

However, I don't want any OCN members using even this one because they can get much better results by asking here in OCN's Power Supplies forum.


Quote:
Originally Posted by phantasmor View Post
well.... i was expecting replies..... i guess i am disappointed..... i find this stuff interesting.... and fun..... oh well, i will stick to what i have been doing...
It sometimes takes a while to get replies. Be patient; this thread is basically still a newborn.
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i5-2500K @ 4.5GHz (1.368-1.384V fixed voltage) ASUS P8P67 EVO B3 (UEFI ver. 1850) GTX 780 ASUS DirectCU II (1228 / 6300, 1.180V) G.SKILL Ripjaws X 8GB (2 x 4GB) 1866MHz, CL9 
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It's a computer!
(19 items)
 
  
CPUMotherboardGraphicsRAM
i5-2500K @ 4.5GHz (1.368-1.384V fixed voltage) ASUS P8P67 EVO B3 (UEFI ver. 1850) GTX 780 ASUS DirectCU II (1228 / 6300, 1.180V) G.SKILL Ripjaws X 8GB (2 x 4GB) 1866MHz, CL9 
Hard DriveHard DriveHard DriveOptical Drive
250 GB Samsung 840 EVO (C:\) 250 GB Samsung 840 EVO (D:\) 150 GB WD VelociRaptor Samsung SH-S243N 24x DVD Burner 
Optical DriveCoolingOSMonitor
Samsung SH-S203N 20X DVD Burner Thermaltake Frio Win 7 Home Premium x64 SP1 Retail AOC G2460PG (24" 1920 x 1080 144Hz G-SYNC) 
KeyboardPowerCaseMouse
Filco Majestouch 104-key Cherry MX Blues w/NKRO Corsair HX650 (Bronze, ordered on 12-12-2009) CM 690 Intellimouse Optical (1.1A) 1000Hz polling rate 
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post #8 of 16
Thread Starter 
Quote:
Originally Posted by TwoCables View Post
It sometimes takes a while to get replies. Be patient; this thread is basically still a newborn.
i guess.... i really find these things fascinating and i would really like to know how other people do it.... and i often wonder why people find these things mundane, i think anything to do with computer architecture is cool, especially the psu
Edited by phantasmor - 4/16/11 at 9:51pm
post #9 of 16
Quote:
Originally Posted by TwoCables View Post
That is actually one of the worst online PSU calculators on the internet. No OCN member should be using a PSU calculator, but if you must use one then use this one:

http://extreme.outervision.com/psucalculatorlite.jsp

However, I don't want any OCN members using even this one because they can get much better results by asking here in OCN's Power Supplies forum.



It sometimes takes a while to get replies. Be patient; this thread is basically still a newborn.

lol their psu calc says i need around 800 watts for a i7@4300 with 2 5970s and 3 hardrives and 10 fans i only got 1 5970 and 5870 but with clocks im running probly around 750-800watts.
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SABERWOLF
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XEON-WOLF
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CPUMotherboardGraphicsRAM
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Samsung EVO 850 500 EK-SBAY Dual DDC 3.2 PWM Serial Alphacool NexXxoS ST30 Full Copper Radiator 360 Hardware Labs Black Ice SR2 Multiport Black Car... 
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post #10 of 16
Quote:
Originally Posted by phantasmor View Post
i guess.... i really find these things fascinating and i would really like to know how other people do it.... and i often wonder why people find these things mundane, i think anything to do with computer architecture is cool, especially the psu
I think one possible reason why people think PSUs are boring is perhaps because most people seem to think that a power supply is just a power supply. People are far more excited about things like CPUs and graphics cards because when they're upgraded, the difference is noticeable.

However, I think the PSU is my favorite part of the entire computer system! After all, the system is nothing without it.


Quote:
Originally Posted by Bal3Wolf View Post
lol their psu calc says i need around 800 watts for a i7@4300 with 2 5970s and 3 hardrives and 10 fans i only got 1 5970 and 5870 but with clocks im running probly around 750-800watts.
Interesting, because AMD recommends an 850W power supply to power a system with two 5970s in it!
It's a computer!
(19 items)
 
  
CPUMotherboardGraphicsRAM
i5-2500K @ 4.5GHz (1.368-1.384V fixed voltage) ASUS P8P67 EVO B3 (UEFI ver. 1850) GTX 780 ASUS DirectCU II (1228 / 6300, 1.180V) G.SKILL Ripjaws X 8GB (2 x 4GB) 1866MHz, CL9 
Hard DriveHard DriveHard DriveOptical Drive
250 GB Samsung 840 EVO (C:\) 250 GB Samsung 840 EVO (D:\) 150 GB WD VelociRaptor Samsung SH-S243N 24x DVD Burner 
Optical DriveCoolingOSMonitor
Samsung SH-S203N 20X DVD Burner Thermaltake Frio Win 7 Home Premium x64 SP1 Retail AOC G2460PG (24" 1920 x 1080 144Hz G-SYNC) 
KeyboardPowerCaseMouse
Filco Majestouch 104-key Cherry MX Blues w/NKRO Corsair HX650 (Bronze, ordered on 12-12-2009) CM 690 Intellimouse Optical (1.1A) 1000Hz polling rate 
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Basic, but premium round X-Fi Titanium HD Klipsch ProMedia 2.1 (with 16 AWG Monster Cable... 
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It's a computer!
(19 items)
 
  
CPUMotherboardGraphicsRAM
i5-2500K @ 4.5GHz (1.368-1.384V fixed voltage) ASUS P8P67 EVO B3 (UEFI ver. 1850) GTX 780 ASUS DirectCU II (1228 / 6300, 1.180V) G.SKILL Ripjaws X 8GB (2 x 4GB) 1866MHz, CL9 
Hard DriveHard DriveHard DriveOptical Drive
250 GB Samsung 840 EVO (C:\) 250 GB Samsung 840 EVO (D:\) 150 GB WD VelociRaptor Samsung SH-S243N 24x DVD Burner 
Optical DriveCoolingOSMonitor
Samsung SH-S203N 20X DVD Burner Thermaltake Frio Win 7 Home Premium x64 SP1 Retail AOC G2460PG (24" 1920 x 1080 144Hz G-SYNC) 
KeyboardPowerCaseMouse
Filco Majestouch 104-key Cherry MX Blues w/NKRO Corsair HX650 (Bronze, ordered on 12-12-2009) CM 690 Intellimouse Optical (1.1A) 1000Hz polling rate 
Mouse PadAudioAudio
Basic, but premium round X-Fi Titanium HD Klipsch ProMedia 2.1 (with 16 AWG Monster Cable... 
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