How to Purchase a New PSU

vincec

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Hello All,

My System:
512 RAM
Asus Mobo
AMD Duron 800mhz
nVidia GF2 MX400
20gig WD ATA
80gig WD ATA
110gig WD ATA (3 hard drives total)
CD Burner
DVD Reader (not burner)
Lots of fans
Allied 450w PSU, under 1 yr old

Well first, it is my belief that my existing PSU, an Allied 450w unit, is dying. The 5v figures are constantly fluctuating, according to my motherboard readings. So I will start by asking if there are any diagnostic tools to use, to properly read/diag a PSU? Also, what are acceptable variatons in the +5v and -5v readings? My motherboard is saying that my variations are too much. the -5v reading will sometimes read around -2v, which it flags in red, and warns me of the situation during startup.

For my setup listed above, how much power should I have? Is 450w enough for what I have listed above? Is it possible the 5v fluctuations can just be ignored?

I am considering buying and adding either a WD 200gig or 300gig HD to my setup listed above. Adding that to the mix, how much power should I have then?

What PSU brands are the best? Which are mediocre? I would prefer to buy a high-line brand, that will last me forever. I was considering buying this one from Newegg: http://www2.newegg.com/Product/Product.asp?Item=N82E16817159016 . I am willing to spend about 100 bucks on a new PSU.

Any help is greatly appreciated. As you can see, I asked a bunch of questions here. But thank you very much to those to reply!


- Vince
 

RichPLS

Champion
Antec True 550 watt is a good one for under $100, so is the Fortron Source 550 watt same price.

<pre><font color=red>°¤o,¸¸¸,o¤°`°¤o \\// o¤°`°¤o,¸¸¸,o¤°
And the sign says "You got to have a membership card to get inside" Huh
So I got me a pen and paper And I made up my own little sign</pre><p></font color=red>
 

vincec

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Thanks. Is 550 enough? Do you think the 450 that I have right now is too little, and that is why the 5v readings are fluctuating?


- Vince
 

Crashman

Polypheme
Former Staff
My 400W unit powers 2 SATA hard drives via adapters, 1 ATA drive, 1 ZIP drive, 1 DVD-RW, 1 DVD-ROM, 1 Floppy, a SCSI card, a modem, a TV tuner card, an All-In-Wonder X800 XT, an overclock P4 2.6C, and 1024MB of RAM via 2 sticks. Oh, and a USB card reader.

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
 

vincec

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Hm, okay. Then my 450w Allied supply should be more than enough for what I have? Is Allied a decent brand? And is it a bad sign that the +5v and -5v readings are fluctuating on my PSU?


- Vince
 

Crashman

Polypheme
Former Staff
Allied is a cheap PSU, considered by some to be better than other cheap PSU's. And that kind of fluctuation would be bad, I'd check it with a voltmeter to see if it's real.

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
 

vincec

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I'm assuming it is. The BIOS reads it, and this ASUS Probe software that I have reads it.

The funny part, is that I bought this PSU from Newegg. It was rather expensive.


- Vince
 

Crashman

Polypheme
Former Staff
Really...I thought Allied were middle of the road, basic quality, better than garbage power supplies at higher than garbage prices...

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
 

RichPLS

Champion
Antec
Enermax
Fortron Source
PC Power and Cooling
OCZ
Seasonic
ThermalTake
Zippy

Are some good brands also

<pre><font color=red>°¤o,¸¸¸,o¤°`°¤o \\// o¤°`°¤o,¸¸¸,o¤°
And the sign says "You got to have a membership card to get inside" Huh
So I got me a pen and paper And I made up my own little sign</pre><p></font color=red>
 

vincec

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RichPLS

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I have not heard any great reviews on Coolmax so do not know how good they are personally.
<A HREF="http://www2.newegg.com/Product/Product.asp?Item=N82E16817103512" target="_new"> Here is an Enermax 535 watt $100</A>
and it has dual 12v rails.


<pre><font color=red>°¤o,¸¸¸,o¤°`°¤o \\// o¤°`°¤o,¸¸¸,o¤°
And the sign says "You got to have a membership card to get inside" Huh
So I got me a pen and paper And I made up my own little sign</pre><p></font color=red>
 

vincec

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What does it mean to have dual 12v rails?

Also, someone told me that a power supply reall should have active PFC? Is this true? Is it bad if it doesn't have it?

- Vince
 

RichPLS

Champion
A rail is the delivery system for power. On PSU's these rails are divided into +3.3v, +5v, +12v, -5v and -12v. The important ones for us to look at are the positive rails. These will be specified to deliver an amount of amps per rail. w = v * a. This gives us the output in watts of the PSU. Having 2 - 12v rails distributes the power of two distrubution lines, thus providing cleaner and more stable power.


<pre><font color=red>°¤o,¸¸¸,o¤°`°¤o \\// o¤°`°¤o,¸¸¸,o¤°
And the sign says "You got to have a membership card to get inside" Huh
So I got me a pen and paper And I made up my own little sign</pre><p></font color=red>
 

vincec

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Ah I see, thanks for that explanation! Is it also important for a PSU to have "PFC"? I don't even know what that means, haha.


- Vince
 

RichPLS

Champion
PFC is Power Factor Correction. Power Factor is a measurement of how effectively power is being used, and is expressed as a number between 0 and 1, with the high number meaning that power is being used effectively.
There are two types of PFC, passive and active. Passive uses a capacitive filter on the AC input to maintain the inductive load, without an addition of power. Active uses a circuit to match the resistive and inductive loads.


<pre><font color=red>°¤o,¸¸¸,o¤°`°¤o \\// o¤°`°¤o,¸¸¸,o¤°
And the sign says "You got to have a membership card to get inside" Huh
So I got me a pen and paper And I made up my own little sign</pre><p></font color=red>
 

vincec

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So then Active PFC is better I would assume? Is there a guide on this site for PSU's? I looked but could not find one.


- Vince
 

RichPLS

Champion
<A HREF="http://www.coolerguys.com/840556018889.html" target="_new"> For $155 you can get the best! </A>
680watts with active PFC and 3 - 12 volt rails.

This one will be a keeper, and price is excellent for the level of quality and power you get!

<pre><font color=red>°¤o,¸¸¸,o¤°`°¤o \\// o¤°`°¤o,¸¸¸,o¤°
And the sign says "You got to have a membership card to get inside" Huh
So I got me a pen and paper And I made up my own little sign</pre><p></font color=red>
 

vincec

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Okay, thanks for all of your help everyone! I will have to consider all of this and just make a decision!


- Vince
 

RichPLS

Champion
Remember to check out that <A HREF="http://www.coolerguys.com/840556018889.html" target="_new"> ThermalTake 680 watt PSU </A>
I linked above. I know it is a little more than you were looking at, but you are leaning towards quality and reliability, and you won't find a better performer for less than this price. It has everything you need for now and the future.

<pre><font color=red>°¤o,¸¸¸,o¤°`°¤o \\// o¤°`°¤o,¸¸¸,o¤°
And the sign says "You got to have a membership card to get inside" Huh
So I got me a pen and paper And I made up my own little sign</pre><p></font color=red>
 

morbidangel

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1) best way to read voltages is with a volt meter.
2) should not change more than .25-30 volts.
3) 450 should be ok your cpu is not very power hungry nor is your video card.
4) get 500+ just to be on the safe side, considering you might upgrade your video card or cpu down the road.
these reding you cannot ignore
5) for around 100 you can get a fortron blue storm for about $80.
 

Renegade87

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May 19, 2001
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vincec,

What is your budget for this new PSU?

The manufacturers RichPLS listed earlier make solid units. Good advice. I might not necessarily put Tt (Thermaltake) in such elite company as PCP&C or Zippy, but that's just my opinion.

The Fortron Source Blue Storm mentioned earlier is a very good choice. Especially at $90 or so (for the 500w model). Another good choice would be the OCZ OCZ420ADJ ATX 420W.

Good Luck with whatever you decide, but get that Allied out of there!

"Nuke em till they glow, shoot em after dark"