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12v line CPU & GPU What else ?

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July 22, 2012 1:29:46 PM

If I have a 95W CPU (8amp) and 2X 75W GPU (25amps) what else uses the 12v line ? I am thinking of getting a new psu with 48 a 12v line will this be enough ?
my present kit includes Samsung 128 SSD + samsung 500gb HDD, a dvd rewriter and multi card reader. I may use a PCI TV /sat card as well.
there is also a 120mm front fan and 200mm side fan

More about : 12v line cpu gpu

a c 79 à CPUs
July 22, 2012 1:59:10 PM



and that helped a lot.

the two gpus at 75W each would only equate to just over 12 amps. (150/12 = 12.5)

the 25amps that they quote is whole system power, but then you are accounting for that twice, if not three times if you include your own 12V calc.

48A@12V is about 575W so I think you are fine. if not overkill. I would say (if you haven't already brought things) that 1x 150W gpu would be better than two small ones



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a b à CPUs
July 22, 2012 2:07:30 PM

How did you get 2x75W/12V = 25A? It's 12.5A.

pretty much.everything uses the 12V line. Your looking at a 600W PSU which can power any single card, but why no system specs/PSU model? Need details and need to know what PSU. Some are garbage
Anonymous
a b à CPUs
July 22, 2012 2:09:41 PM

what chipset?
AMD can use between 13- 22 watts
http://en.wikipedia.org/wiki/Comparison_of_AMD_chipsets...
intel chipsets can use 4.7 to 6.7 watts.
http://en.wikipedia.org/wiki/List_of_Intel_chipsets#5.2...
generally a HD uses 10 watts of the 12 volt rail (they use 5 volt also)
http://ixbtlabs.com/articles2/storage/hddpower.html
RAM is about 8 watts a stick.

avoid outdated online PSU guides if you can. the data is outdated since power consumption for components have gone down. a simple google can get you more accurate information.

also don't assume just because the max TDP is 95 watts that is what the cpu draws. my i3 is 65 watts TDP but never goes over 40 watts. if you error on the side of caution is ok. but if it leads you to get a 850 watt PSU for a system that will draw no more than 350 watts; thats as bad as getting too little of a PSU.
a c 122 à CPUs
July 22, 2012 2:26:56 PM

12V rails power just about every major load in the PC... HDDs, FDDs, DVD/BD, fans (basically nearly all electromechanical devices), heaps of point-of-load regulators on the motherboard and add-in boards, etc.

3.3V and 5V are there mainly for legacy purposes from the days where manufacturers were often using linear regulators because PWM regulators were too large and expensive. With today's very low voltage high-current semiconductors and high demand for improved efficiency, linear regulators are no longer practical. With manufacturers forced to adopt switching point-of-load regulators, most applications migrated to 12V feed which allows more efficient operation along with cheaper and smaller input components.

I would not be too surprised if the next standard after ATX went almost entirely 12V with only a few amps for 5V USB.
July 23, 2012 6:06:58 AM

thanks so much all of you I will do some more checking at those sites and post my present and hoped for upgrades and all my specs
August 2, 2012 7:00:22 PM

Sorry about maths error,still nervous on forums. I am still on hols but have a laptop + free Wifi,have had a look at the websites suggested by you all. Am now in the know thanks.
my pc is made up of Asrock 990fx 3 extreme mboard and just added 128gb samsung SSD , pair of Kingston 4gb 1600, running at 1333on my old cpu Athlon 2 630 2.8Mhz,1 x radeon HD4770 and 1x asus HD4770 with Hdmi both got at different times at good price. the psu is a EzCool 500w, LG blueray DvD REw ,a sat/tv card .Mostly used as Tv converting to household TVs .I do play games just got COD mod war 3 still after Macorov. Am waiting for for half life 3. I want to get a AMD FX 4100 and try some over clocking, and looking at Antec 620W Gamer fixed leads. these last things got me asking what current I needed ,card reader and 120 and 200 fans.thanks for all your help
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