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Is testing a PSU with no load just as effective as full load?

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February 5, 2013 9:06:17 PM

I want to buy a power supply tester so I can test power supplys such as ones that come with cases just in case (only if the build uses low power). Also just to test older power supplys. Anyway back to my question, if I tested it with just the tester and no other load is it just as effective as high load? And if not how would I set the load higher? And what would be an acceptable voltage like is 12.5V ok on a 12v rail? I also find it funny that rosewill sells power supply testers (it's cheaper so I'll probably get one of those) when their PSUs suck.
a b ) Power supply
February 5, 2013 10:32:11 PM

No its not as effective as a high load, its just good enough to determine if the supply is dead.
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February 5, 2013 10:41:03 PM

Well how do I get it to high load?
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a c 80 ) Power supply
February 5, 2013 10:43:24 PM

Loaded tests are always harder on the power supply. This is why many cheap power supplies power a low powered system fine, but fall out of spec at higher loads.

Rosewill's power supplies are getting better to be honest.

ATX specs

12V ±5% MIN 11.40 MAX 12.60 <-This used to and MAY still be 10%, but I would like to see less.
5V ± 5% MIN 4.75 MAX 5.25
3.3 ±5% MIN 3.14 MAX 3.47
-12V ±10% MAX -10.80 MIN -13.20 <- I know it looks strange, but I think that is how it should look
+5VSB ±5% MIN 4.75 MAX 5.25

Also important is how much the voltage fluctuates and ripple in the voltage. Cheap testers will NOT check that.

EDIT to reply to your other post.

Reviews sites use huge banks of resistors to eat the extra power(and feed all that heat back into the power supply for extra stress).
For you, get an OLD system and as many hard drives and other hardware as you can :)  , unless you want to built a load tester, you would need some heavy duty resistors(hmmmm 12 volt electric car heater rated at 10 amps or 120 watts :p . This does not load the lower rails, but most newer power supplies get those off the 12 volt rail anyway) to make the kind of load a power supply can power.

I can NOT recommend playing with power or wiring in a car heater :) 
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a c 1178 ) Power supply
February 6, 2013 2:03:40 AM

Proper loading will require one or more of these programmable load testers:
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February 13, 2013 4:53:13 AM

Best answer selected by melikepie.
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a c 291 ) Power supply
February 13, 2013 11:57:01 AM

melikepie said:
I want to buy a power supply tester so I can test power supplys such as ones that come with cases just in case (only if the build uses low power). Also just to test older power supplys. Anyway back to my question, if I tested it with just the tester and no other load is it just as effective as high load? And if not how would I set the load higher? And what would be an acceptable voltage like is 12.5V ok on a 12v rail? I also find it funny that rosewill sells power supply testers (it's cheaper so I'll probably get one of those) when their PSUs suck.


Hi - ko answered you on the tester part of your question.

I just wanted to correct your statement that Rosewill PSU's suck.

That may have been the case a few years ago, but is certainly
not the case today. Their Capstone, Fortress, and Tachion
series of PSU's are all very good to outstanding PSU's.
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