# [SOLVED] About graphic card amperage



## stanley85 (Jul 30, 2007)

Anyone knows where to get the list for amperage usage for 3d card? especially ati dx10 base cards. thanks.


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## TheMatt (May 9, 2006)

*Re: About graphic card amperage*

You can calculate it. Volts x Amps = Watts. If you know the current consumption of the graphics card, you can take the total power consumption and divide it by 12 for the 12v the voltage regulators take.

For example, a 100w graphics card will take about 8.33a. This is only the power it takes through the through the +12v line though.

Keep in mind though that there are many many other items in the computer that draw current like the CPU voltage regulator. That regulator also runs off the +12v rail, so you can't expect to buy the minimum amperage.

Bottom line, a good 600w PSU will easily power any single 8600 series card, and a good 750w will power any single 8800 series card.

If you pay and use the pro version of this PSU calculator, it will take into account amperage.
http://www.extreme.outervision.com/psucalculator.jsp


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## dai (Jul 2, 2004)

*Re: About graphic card amperage*

you can get the wattage here and then use matts method of calculating the amps
http://www.atomicmpc.com.au/forums.asp?s=2&c=7&t=9354


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## stanley85 (Jul 30, 2007)

*Re: About graphic card amperage*

i see, thank you very much for the information. 

edit: but then if count for: let say the 8800 gts 320mb is about 103 watt, and my other component spec use up 180 watt (cpu c2d e6600, 1 hdd, 1 dvd re-writer, 2 ddr2), so the total would be approximately 283 watt, doesn't it means that any psu with 300 - 350 watt will be enough (pure power)? with the condition that i don't overclock anything.(assume not considering of future upgrade anything in this pc)


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## TheMatt (May 9, 2006)

No, because there are a lot more things. The hard disk spindle motor is another thing that gulps up power. If you try to boot an 8800GTS with a 300w, it won't turn on. :wink:

Take a look at this: http://www.extreme.outervision.com/psucalculatorlite.jsp

Calculate 30% of the total and then add it to account for PSU inefficiency,


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## stanley85 (Jul 30, 2007)

ok, i put in all the spec with 30%, the calculator give me 377watt, (isn't 30% will be a bit too much?) sometimes i also confuse with it, i had been told that a 8800 gts need at least 32 amp for v 12 to power the card.

this is what i put:
single processor, high end -desktop, intel c2d e660, 90%tdp, 2 sticks ddr2 ram, 1 hdd 7200 rpm, 1 dvd-rw/dvd+rw, 1 80mm fan, 1 120mm fan, 100% peak load, and 30% capacitor aging. result = 377 watt


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## TheMatt (May 9, 2006)

You want to do about 15% Cap aging. Then, add 30% to that result.

What video card did you put in?


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## stanley85 (Jul 30, 2007)

8800gts 320mb. hmm, even if pure power psu also need take 30% for psu inefficiency? which means that we need to manually add another 30% for the total watt, like 318watt (15% aging) + 95.4 watt(additional 30%) = 413.4 w ?
thanks.


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## stanley85 (Jul 30, 2007)

edit: type wrong, sorry.


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## TheMatt (May 9, 2006)

Keep in mind your PSU is going to have to sustain that power output throughout its useful life. You will also want room to accommodate upgrades. That is why I would go with a 700w.


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## stanley85 (Jul 30, 2007)

sorry i think i forgot the meaning of psu inefficientcy, that you pointing at the psu that rate at 500watt, with the efficientcy 80% = 400w actual output? so when i buy the psu i have to make sure it has more than 318w in actual power output. ya i do agree that the power output will decrease. thanks for your info, it make me understand more on the psu wattage.


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## koala (Mar 27, 2005)

The extra 30% you add to the total is because most PSUs only run at about 70% efficiency, and the better ones 85%. Over time the efficiency decreases which is why you need to add the extra to the calculated total.


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## dai (Jul 2, 2004)

the 30% is based on the average supply having a efficency rate of 75%
one with 80% you would add 25%
one with a 65% you would add 50%


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## stanley85 (Jul 30, 2007)

oh ok.. thanks a lot.


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