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How to tell a good psu from bad

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December 18, 2005 7:33:11 PM

Well how do i check to see how "good" my psu is... i m having some issues (games not running as well as they should) but am not sure where they are coming from... i dont reall understand all this talk of amps in the rail... any1 care to explain how i go about measuring it and how many amps is good? My system specs are in my sig... thx...

More about : good psu bad

December 18, 2005 8:30:58 PM

alright think u can list your psu model? you normally want around 18 amps on the 12v rail (atleast you probably want more) Thats pretty much a requirement. Also poor performance could be the result of viruses/adware/spyware.. make sure your pc is clean.
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December 18, 2005 9:43:33 PM

WOW is the newegg photo tiny or what.. i cant read the amperage ratings...
December 18, 2005 9:48:57 PM

Looks like crappy, imo.
December 18, 2005 10:02:26 PM

ok i did some research on your power supply, its not great.. it only has 12A in your 12v rail... time to swap it out before it blows on you. i recommend an rosewill or an antec. neither have given me any problems and ive gotten like 5 of each already.
December 19, 2005 1:04:05 AM

well im a cheapskate and is there really any serious consequences having a bad psu? like what are symtoms of my comp not getting enough juice?
December 19, 2005 1:12:38 AM

well lets just say that a potential shortage of power could result in a power supply frying... now if ur power supply is "protected" it will only commit suicide.. not homicide & suicide.. i had raidmax psu a while ago.. when it blew on me (it had 13amps on the 12v rail... ) it took my motherboard and hard drive with it... so ya.. its not a good thing...
December 19, 2005 1:15:02 AM

what do u mean by protected? and what is the likely hood of this happening anyways?
December 19, 2005 1:57:15 AM

um if you have a 6600gt and an socket 939 board.. its rather likely... Todays video cards draw power like there's no tomorrow.. i seriously recommend fixing it by getting a better one.

protected is like a "surge protector" so that hwen the psu dies.. it only kills itself.. nothing else in the pc will fry with it.. PSU's tend to kinda send a surge of power when they die frying everything that cant take the extra voltage.. the protected ones will trip a circuit breaker to protect the rest of your components.. i learned hte hard way..

Buget: (depending if u require the 24pin atx connector)
http://www.newegg.com/Product/Product.asp?Item=N82E1681...
http://www.newegg.com/Product/Product.asp?Item=N82E1681...

Performance:
http://www.newegg.com/Product/Product.asp?Item=N82E1681...
December 19, 2005 2:46:00 AM

well i dont have that much- (check my sig... )... and my pc is surge protected so ill just keep my psu till it fires and then get a new one i think... if it fires itll only kill itself rite???
December 19, 2005 3:11:24 AM

oh im sorry iwas using the "surge protector" as a analogy. there is a protector built into the power supply that keeps the other components in the comptuer functional in the event hte power supply goes.. thats not a standard feature. not all power supplies do that. I dont know if yours does it or not but its not something i want to test.
a c 158 ) Power supply
December 19, 2005 2:23:12 PM

LMAO!! :lol: 
December 19, 2005 4:16:06 PM

Crash has laid out the line for the right budget/performance PSU for you...
and if $40 is too much, I am speechless...
December 21, 2005 1:33:04 AM

well im not sure what im gonna do cuz i dont ahve any current problems with my psu as of now and i check the 12c rail and its 18A which aint bad... so ill just stay with this guy till he kills himself....
December 21, 2005 4:02:19 PM

Quote:
well lets just say that a potential shortage of power could result in a power supply frying... now if ur power supply is "protected" it will only commit suicide.. not homicide & suicide.. i had raidmax psu a while ago.. when it blew on me (it had 13amps on the 12v rail... ) it took my motherboard and hard drive with it... so ya.. its not a good thing...


promethas, you not read this ^^^

If your psu dies, chances are the rest of your hardware will go with it

For the money that you spent on your hardware, is it really worth powering it with a pos psu?

Its sort of like buying a Ferrari 360 and putting Diesel in it, okey fine it may work for a bit, but its going to be slow, and you just know that the engine isnt going to hold up.

I live in the Uk, and we pay in £ whatr you guys pay in $ for power supplys, my Enermax Noisetaker 485W cost me £70, its like $69.99 on Newegg (anyone up for the conversion? But i paid almost double for it). C'mon guys, there is no excuse for using shite to power your pc :p 
a b ) Power supply
December 21, 2005 4:58:46 PM

Your video card is probably throttleing itself down . This is caused by overheating or not getting enough power.
Why would you chance blowing your whole system by using a cheap power supply.

I have had one blow. It took the motherboard,modem, video card and memory with it. Only thing it did'nt kill was the cpu.
Do yourself a favor and follow Crashmans advice.
December 24, 2005 12:13:16 AM

Ok im gonna buy a new psu.... but besides the one u recomeded what is one with good expandibility i dont want to buy this one and be forced to buy another one when i do my next build... i have 60 bucks to spend...
a c 158 ) Power supply
December 24, 2005 12:06:34 PM

FSP 450W has good expandability for you.
December 24, 2005 2:28:14 PM

Watts don't mean everything. Tagan has more amps on the +12v rail, supports SLI, uses the 20+4 pin configuration, can have split +12v rails or you can make them become 1 +12v rail, and has more molex connectors than you would know what to do with.
December 24, 2005 2:30:21 PM

The "surge protector" is actually a little device called an MOV. It can only blow once. Also, for your information, watts should me everything. Watts are the product of volts times amps. 18amps x 12v = 216 watts. It just matters which rails they chose to distribute those watts. Any decent power supply will have individually fused rails, aswell as an mov. Spend the money! Go get a good powersupply
December 24, 2005 2:49:31 PM

This is a really cheap psu, it has oveload and short circuit protection. If this one were to blow up, it would not take out anything. And after a mail-in rebate it is only $15. It is only $25 if you don't feel like waiting 3 months for your $10 back. http://www.newegg.com/Product/Product.asp?Item=N82E1681...

Nevermind, I just looked at your s again. Yours will only die. It will not take anything out. However, crappy power supplies do more than just kill stuff when they die. They cause all sorts of performance problems. You should still upgrade to a 550 watts PSU or better.
December 24, 2005 2:57:24 PM

Why spend more for a 550W PSU when his system is only going to use maybe 300Watts? And in the next few years when he wants to upgrade/ build a new PC he still probably won't need a 550Watt PSU. Get something with more amps on the +12v rail.
a c 158 ) Power supply
December 25, 2005 11:53:14 AM

Don't act like the Enermax is a POS. If you don't know what you're talking about then step back and think twice. Amps are important, but you don't have to spend an arm and a leg to get a good quality PSU. I personally think some of the high-end PSU mfrs are making more money on their names than they are on their PSUs. Tagan being one of those...
FSP has GREAT PSUs, hell that 400W for $40 is sufficient for his system and the $50 450W would allow enough power for a future build. They are half the price of the Tagan. Spend all of the money you want on the name of a PSU - I think i'll buy quality at a good price.
December 25, 2005 5:25:05 PM

Uh, d00d, I'm almost certain that $25 power supply is a rebranded PowMax. My dealer sells those. My dealer also repairs around twenty systems a month for "lightening strikes" when we don't even get lightening here.

He sells these crappy power supplies that DO blow components. Then he gives the power supply to me, I replace a couple capacitors, and he puts them back into systems. He makes a killing off "lightening strikes" when the real cause is the power supply YOU RECOMMENDED!
December 26, 2005 1:06:09 AM

The "lightning strikes" that you refer to are called power surges. An MOV is a surge protector. That PSU that I was going to recommend, has an MOV. Unless the specs are lying, it cannot damage any system components. However, I did not recommend it. I will also say that, you should not use more than %80 of the available power per rail for continuous use. The 12watt 12v rail is just not enough. It will almost certainly die eventually.
December 26, 2005 1:08:04 AM

Quote:
I replace a couple capacitors, and he puts them back into systems.


If you are replacing capacitors, then the units you are reffering to do not have MOV's. The unit I was referring to does
December 26, 2005 1:32:16 AM

All power supplies have capacitors. And these cheap capacitors DON'T REQUIRE a strong power surge to fail, read badcaps.org, the guy is getting capacitor failures in 6v caps by connecting a 5v battery.

You're dreaming d00d, living in a world of theory. I live in a world of reality. I realize that the bad capacitors in question can fail under normal use. And the capacitors are needed even when the power is pure and clean, to compensate for the constantly changing load.
December 28, 2005 2:35:06 PM

Since you guys said amps are important too, how do you determine the total 12v amps. like if it lists +12V1@20A, +12V2@18A and I only want to use one video card then is it 12v@38A. I don't think I get it. Because i've been comparing mfg for 7800 cards and they list psu requirements as 400+ power supply with 12V@26A or 28A.
December 28, 2005 4:55:11 PM

This is what I'm wondering too. If you add up the amps on both 12V rails, is it the same as having that number of amps on one rail? Let's say XYZ device requires 25 amps, so if you have two rails each doing 18, would that be sufficient since that's 36 total? I find the subject confusing still.
December 28, 2005 7:13:56 PM

This is a funny one. If you look at the charts on the side of many power supplies, they will often say something like 12v1 20A, 12v2 20A, and under that have a combined rating that's lower, like maybe 36A. There's a reason for that!

Most "Dual Rail" power supplies don't really have Dual Rails, but rather Dual Circuit Breakers on one rail. That rail might handle 36A, but between the main rail and the outputs it's split across two circuit breakers.

And there's a reason why they wouldn't just use two 18A breakers: You might want to pull 16A peak on one side and 20A peak on the other. So they give you two 20A circuit breakers rather than two 18A...

Why don't they just use one 36A for both rails then? Because Intel told them not to. It turns out that if you short out a connector, you're more likely to have a wire melt with possibility of fire if you have higher amperage available to that wire.
December 28, 2005 7:38:57 PM

Thanks Crashman. So, is using a dual 12V PSU just as stable as a single rail one? Is there any advantage or disadvantage in using one type over the other?

It seems like most PSUs are heading towards dual now, but I still see some people think that single is the best way to go.

Which would be best for a 6800GT AGP card?
December 28, 2005 7:59:11 PM

Tom's did a review on psu a couple of months ago and said that the enermax Noisetaker have the Cleanest power available (stay in voltage best). I am running one now and think its great and quiet.
December 28, 2005 8:46:45 PM

Single allows you to bias the load more highly to one side, while dual provides better short circuit fire protection. Then again, I haven't seen many PC fires lately...
December 28, 2005 8:57:47 PM

Yeah, that's what I've heard, that dual is supposedly safer. Would a 6800GT AGP benefit more from a single rail or dual rail? What about a pair of 7800's in SLI mode?
December 28, 2005 9:28:47 PM

I can't really say that anything benefits from this split single rail that they're calling dual rail. As for benefitting from single rail, high-capacity power supplies normally have enough room to bias amperage to either side.
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