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Power Supply + Performance

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April 16, 2010 5:59:39 AM

I installed a PNY GeForce FX 9800 a while back into a system I built that didn't have a PSU with the minimum requirements for wattage, but it still worked. I recently upgrade the PSU after about... 2 years. The minimum PSU requirements is 400w with a 12v rating of 26a, but mine is a 480w with only a 12v rating of 16a...

In order to receive optimal performance from both PSU/GFX card, do I HAVE to have a 12v rating of 26a, or is 16a ok since I'm 80w over the minimum?

Also, I believe I MAY have had my previous PSU upside down... I know it sounds stupid, but it was the only way it would fit. I've noticed a huge change in temperature in my room. Before I upgraded, my room was unbearable most of the time and it's already a lot cooler just putting in a more powerful PSU in the correct direction.
a b ) Power supply
April 16, 2010 6:13:32 AM

Your PSU probably has 2 12v rails I doubt your 480 watt unit only puts out 16 Amps even the cheapest PSU have at least 20 Amps. Check the specs you will see 12vA and 12vB or 12v1 and 12v2. The 9800gt would not be able to run if you only had 16 Amps you would get random shut downs and BSOD constantly. Usually the two rails will also have a combined output I would imagine its somewhere between 25 and 30 amps for the combined output. The wattage of a PSU will mean almost nothing if it cant output the proper Amps 16 Amps would only equal about 190 watts.

What is the make and model of the PSU for me to verify.
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a c 144 ) Power supply
April 16, 2010 6:23:11 AM

It's not the minimum power requirements in watts that's the problem. It's the total 12 volt current available that is the important point. They are not the same thing.
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a b ) Power supply
April 16, 2010 8:07:35 AM

saaiello said:
Your PSU probably has 2 12v rails I doubt your 480 watt unit only puts out 16 Amps even the cheapest PSU have at least 20 Amps.


You obviously don't deal with cheap PSU's do you? (probly a good thing) I have seen many a 480w 16amp unit.

However, the fact that his held up instead of blue smoke suggests you may be right bout the dual rail.
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a c 276 ) Power supply
April 16, 2010 2:29:04 PM

Oh, that POS unit.

The reason it only has 16A on the 12V rail is because its 480W peak, so you arent 80W over what it wants you are actually 70W under recommended. Swap that sucker out ASAP, something like the corsair 400CX is inexpensive and provides a lot more power. Or you could get a PSU that you wont need to upgrade next time you want a GPU upgrade like this seasonic for a bit more.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Right now you stand a good chance of killing the PSU and having it kill something else in the process.
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April 16, 2010 3:13:10 PM

Well, when I bought my GFX card, I lost my job shortly after and had been jobless for almost a year. I JUST got another job two days ago and training doesn't start until Monday... So I'll have to wait for my first pay check, lol. At the moment, it's the best I can do. Thanks for the help guys.
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a b ) Power supply
April 16, 2010 5:04:21 PM

FALC0N said:
You obviously don't deal with cheap PSU's do you? (probly a good thing) I have seen many a 480w 16amp unit.

However, the fact that his held up instead of blue smoke suggests you may be right bout the dual rail.

LOL your right I never used a cheap power supply I cant beleive that they would do that put only 16 Amps on the 12 volt that is pretty ugly power supply. Yet it almost has 30 amps coming off the 5 volt which is no longer needed like it used to be.
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