PCTech Forums

by **Zin5ki** » Sat Jan 20, 2007 6:00 pm

New person here. Sorry for the abruptness.
On the chart on my PSU (400W Qtechnology semi-fanless) it reads 18A on +12v1 and 18A on +12v2. Does this mean that it can supply a total of 36A on +12v?
I don't know if the currents add up or not, only I want to buy a new graphics card (7600GS AGP) that requires 20A from the +12v rail.
Should it (in theory) be compatible?
Any information would be much appreciated.

by **Gecko** » Sat Jan 20, 2007 9:44 pm

Hello Zin5ki and welcome to our forum.

The short answer is no, the amperage is not cumulative, the 18a rating is the total for both + 12v rails.

Watts always, exactly equals volts times amps
18A times 12v = 216 watts, that would be about half the total PSU rating as it should be.

I am positive that video card does not draw 20 amps they just want to make sure you have enough to power everything else that also runs 12v.

has the best PSU wattage calculator that I know of.
It does not list the individual amps for each 12v item,
but you can however get a good idea of what each device draws in watts and back figure to get the amps.

by **Zin5ki** » Sun Jan 21, 2007 4:17 pm

by **atbsolja** » Sun Jan 21, 2007 4:24 pm

by **Gecko** » Sun Jan 21, 2007 7:49 pm

by **Zin5ki** » Sun Jan 21, 2007 9:46 pm

The MB monitor shows the 12v rail to be around 11.8V.

There is no label on the PSU itself (all the walls of its structure are made of a fine hexagonal mesh for airflow), and the only information I can find is that both 12V rails have a maximum current of 18.0 and a maximum voltage of 12.6 (over voltage & over current latch systems have maximum values of 15.6v and 23A respectively).
Combined power output is, for some reason, only given for the 3.3 and 5 volt rails.

I apologize if these figures aren't helping.

by **Gecko** » Mon Jan 22, 2007 1:05 am

Zin5ki,

I can not find any power specs on the GeForce 7600GS AGP

Your Qtechnology PSU seems to be a quality product and with an honest 400 watt rating.
Based on this and your PSU calculation of 224w, if it were me I would go for it.
After all, device ratings are for peak usage demands not idle usage how often will everything be at peak?
The only time all the peripherals would do this is at boot up and even then not everything will be maxed out.

Please realize that this is a best guess situation for me and I could very well be wrong.

by **Zin5ki** » Mon Jan 22, 2007 4:46 pm

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