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PSU Guide

Discussion in 'General Hardware' started by panchoman, Sep 13, 2007.

  1. panchoman

    panchoman Sold my stars!

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    its not like grafix card long right? i'm too lazy to figure out those numbers. how would you compare the psu to the length of an hdd?
  2. Wile E

    Wile E Power User

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    Hmm, hadn't thought of that, but you will still need to cut, so you can keep the airflow holes open. I was gonna go the sheet aluminum route because I had some extra laying around.
  3. Wile E

    Wile E Power User

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    Well, for a point of reference, an ATX mobo is 9.6" wide. So it's roughly 1.5" shorter than a mobo is wide.
  4. keakar

    keakar

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    i went to "shade tree mechanics institute of technology" :toast::D
  5. Wile E

    Wile E Power User

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    Why do you think I had extra sheet aluminum around? :laugh:
  6. panchoman

    panchoman Sold my stars!

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    lol, i cant do modding and stuff like take aluminium and turn it into a cage for a psu lol. they dont sell like brackets for 5 bucks?
  7. Wile E

    Wile E Power User

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    Haven't seen any, personally. Swiftech sells a whole kit with the psu, relay kit, and brackets for like $150. That's too expensive, as I can buy the psu and relay kit for around $120 shipped. And they don't sell the brackets separately.
  8. panchoman

    panchoman Sold my stars!

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    ah i see, well i'd be fine on the floor lol, how does the relay switch work exactly? i'm sure you have experience there..
  9. Wile E

    Wile E Power User

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    Well, the aux psu requires it's own power source. If you plug it straight in, it's always on. So what the relay kit is for, is to make the psu turn on, only when the main psu is on. The very basic explanation is: You hook the aux psu to the relay kit, hook the relay kit to a molex connector, then plug the relay kit into your electrical outlet. What it does is use the molex to sense when the main psu is on. When the main psu turns on, it opens an electronic switch to allow power to get to the aux psu.
  10. KennyT772

    KennyT772 New Member

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    Pancho it can be clearly assumed you do not like limited lines or Modular power supplies.

    Unless it is a nonstandard form factor psu it is a single transformer aka single rail unit by definition.

    For your repeated question about drawing 20amp from one lead: You will first melt the wire, and secondly only tec's use that much juice where you DEFIANTLY run a separate psu. You wouldn't want to run a 20amp tec on a normal psu, it would trip overcurrent protection on even pcp&c psu's as they all have trip points, they just say they don't.

    For your repeated statements about "lost amperage" take this example.
    You have a power supply that only produces 20amp of 12v. There are two outputs each capped at 15amp.
    Rail one is the ATX 24pin connector and the PCI-E connector, Rail two is the Workstation (8pin eps) connector and a 3molex lead.
    Please explain to me how you are going to waste voltage on this psu.

    BTW those with a OCZ gamexstream power supply (may apply to others with ocz psu's) I just realised my 12v wires are all color coded as to which rail they belong to.
    No stripe - 12v1 motherboard 24pin, molex/sata leads
    Green Stripe - PCI-E 2 connector/2 of the 4 EPS12V leads
    Blue Stripe - 2 of the 4 EPS12V leads
    Black stripe - PCI-E 1 connector
    (for the source nazi http://www.extremeoverclocking.com/reviews/cases/OCZ_GameXStream_700W_1.html)
  11. keakar

    keakar

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    incorrect sir, although some smaller wires arent sufficient for high amps, if you look at the chart here: : http://www.powerstream.com/Wire_Size.htm

    NOTE: The Maximum Amps for Power Transmission - this standard is only used for generator and alternator wires where power is being produced not converted. hence the rediculusly low amp ratings.

    12 guage wire can safely handle 41 amps

    14 guage wire can safely handle 32 amps

    16 guage wire can safely handle 22 amps

    so while i dont see multi rail psu as the only choice, it depends on the user as his needs.

    now a single rail would need limiters if the transformers output exceeded the wires amp rating but as long as this did not occur a single rail can easily supply power needs for most systems
    Last edited: Sep 19, 2007
  12. panchoman

    panchoman Sold my stars!

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    thank you for that explanation. you mind if i use some that (may modify it a bit) for an explanation of the switch while writing about aux. psu's?
  13. panchoman

    panchoman Sold my stars!

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    it can be clearly assumed that i am neutral and on neither side of the situation at the moment because single rail and multi rail psu's are preety much the same thing only with multi rail psu's you have multi wires, which can help limit the amount of load on the wire= cheaper wires can be used in the psu. as for modular, as i said its not a problem, you just get a minor voltage drop, thats all. so i am on neither side as of now. before, i was fighting on the side for the single rail as for a debate(in a debate you're on whichever side you are selected to be on, no matter however much you support the other side) my job was to fight my case as best as i could against the other side, and to see what the eventual outcomes will be. and the outcomes are as i stated before, basically the same thing, seperated into multiple wires to prevent wire overloading. as for the voltage being wasted, keaker has already explained how the voltage can be routed from one source to another via the mobo so that topic is also finished. please find a new topic:slap:
  14. panchoman

    panchoman Sold my stars!

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    yup yup, multi rail psu's are slightly cheaper since they use higher gauage cabling, so thats that.

    anyway, if you guys want to contribute to the guide by writing new material or rewriting some of my material, please pm me. keaker has done a great job at rewriting and cleaning up some of the paragraphs and i'll be adding his stuff very soon. thanks a lot keaker. and also if you want a suggestion kenny, you seem to know the wattage and amperage stuff very well, why dont you write a bit on that? like explain the wattage formula and how psu labels can have incorrect info, the 30% rule, etc. etc. and i'll add that to the advanced portion of the guide. also dont forget that you can easily contribute to this guide just by checking the oem of the psu you have at home via the ul number and making sure it matchs with the brand/oem list, you guys can just post it right on here if you have a different oem then what's listed and if the oem you have on your psu matchs the one i have.
  15. KennyT772

    KennyT772 New Member

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    (I'm going to try to be as non-argumenitive from here on out, so bear with me)

    The Wiring in almost all power supplies is 16ga, with some wires such as 5vsb/-12v/psu-on being smaller gauge (no more than 2-3 amp over the wire). You may verify this yourself by checking any psu's you have against eachother. Some units may have higher than that but I have yet to hear/see/read a review of anything with high gauge wire being noted. Not even the PCP&C psu's have more than say 14ga (which still cannot carry the psu's full amount of current).

    (Heres my contributions to the guide)
    Power supply ratings - The reality of Watts
    Every consumer power supply today has a output rating in watts. Some are the absolute maximum they will output before overload, and some are the normal continuous output.

    When it comes to buying a power supply there are several things you want to pay attention to other than just the wattage. Number one is the brand, as a 1000w psu from one company may be a waste of money vs a 750w from another company. Second is efficiency, which I will outline later. Lastly you want to look for PFC or Power Factor Correction, Modular/Non, Silent, Asthetics.

    All of this wattage business generally confuses most people, as logic would tell you more is better although that isn't always the case. In terms of wattage the main thing to look for is the total number of +12v Amps. This is where the "more is better" mantra rings true. Finding that number for any given power supply (referred to as PSU from now on) can however be a slight challenge.

    Take my psu for example. I have a OCZ 700w GameXStream psu (NewEgg link http://www.newegg.com/Product/Product.aspx?Item=N82E16817341002).
    According to its specs it produces 700w (unknown if max or continuous) and the specified current for each voltage:
    +3.3@36A (118.8w)
    +5V@30A (150w)
    +12V1@18A (216w)
    +12V2@18A (216w)
    +12V3@18A (216w)
    +12V4@18A (216w)
    -12V@0.8A (9.6w)
    +5VSB@3.0A (15w)
    Already you should start to notice that if you add all of those up you are well over 700w and above even 1000w. If the psu output those kind of numbers all the time it would produce 1157.4w, so something has to be up if it is only a 700w unit.
    That answer is a current limiter. These are placed in several areas in a psu to prevent overloading a wire to prevent damage or fire, or to prevent overloading the transformer and burning it out. Some of these limit by amps and some limit by watts. While these maximum numbers say the unit is capable of over 1000w the limiters prevent that so you cannot overheat the psu. According to the sticker on the side of the psu this is how the numbers break down.
    The combined output of the +3.3v and +5v is < 155w, combined output of all +12v is <50amp or 600w, combined output of -12v and +5vsb is 20w. Combined +3.3v, +5v, +12v must be under 680w, total output <700w. Maximum amperage is 70amp.
    This may seem complicated but it describes how these limiters are setup inside this unit.

    Now that we have the wattage explained lets talk about finding the correct psu for your computer. Say the computer in question uses roughly 500w full load, with no overclocking. The general rule of thumb is that your computer should only use about 75% of the psu's capacity. This way you have prolonged life of the part, less heat and noise, better efficiency, and overclocking/upgrade headroom. So that means for your 500w computer you would want a unit between 650w and 675. Any psu above 400w should have at least 5/8 of its power on the 12v rail so 650 X (5/8) = about 400w / 12v = 33amp.

    Next you want to narrow your search down to 650w+ units with at least 33amp of current on the 12v rail. Here is where things start to get very interesting - 12v rails. One rail, two rails, three, five, which is right for you? All normal sized psu's have a single transformer that takes the 110v/220v from the wall and turns it into dc. From there the current is changed into 3.3v, 5v, etc. With todays power supplies having so much current on the 12v rail some strange things were starting to happen. Motherboards started pulling so much current that the wires would melt, causing fires or at the least frying the power supply. As part of the ATX12v spec limited rails were introduced to prevent this overload from happening. This spec required a limit of 18a over any one 12v output. Most psu's have 16ga wire, which at the most can supply 22a of current before overheating and melting the wire.

    You are wondering why I just gave you the history lesson, well that is how the multi-rail power supply business started, as a safety spec. Now it just adds more confusion for consumers. What you want to look for is the total output of the rails, not simply 18a times the amount of rails. For this OCZ the max for all rails combined is 50a. Other units may not list a maximum.

    That is all I have time to write for now, I need sleep.
    panchoman and keakar say thanks.
  16. Wile E

    Wile E Power User

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    Np. You can use it if you want.
  17. panchoman

    panchoman Sold my stars!

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    thanks for the contribution kenny, i'll be reading over it, editing it, and adding it tommorow hopeuflly.
  18. panchoman

    panchoman Sold my stars!

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    hey, finally found time to work on the guide. what color should the cautious psu's be?
  19. keakar

    keakar

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    well any color really as long as it is a dark shade so it stands out against the white background.

    how about purple? its color is mixed blue and red and it denotes a choice inbetween blue and red colored choices?

    if you cant decide then post a few choices here in the forum and see how they look, then just delete the post.

    many of the reference material has colored backgrounds so their choice in color doesnt always look good when on white bg.

    EDIT: great job, keep up the good work. :toast:
    Last edited: Sep 24, 2007
  20. panchoman

    panchoman Sold my stars!

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    ty keaker, i've changed the color, and the purple looks excellent. i've also going to be changing 2 oems:

    seventeam has advanced a rank to green. seeing that the manufacture the olmypia and decathalon series for silverstone, which is a very series and all and they make cooler master psu's, those are the 2 man psu brands they work with and both brands are great. they have a sprinkle of products in the ultra line and we know that there are quite a few ultra psu's that are actually very good and now we can say why. also im advancing etasis, which also makes silverstone psu's and their own psu's, seeing that the silverstone psu's are excellent, their own psu's are probably as well.

    and also i'll be updating the guide with the stuff you sent me and then some tec stuff by wile e and some supplemental wattage stuf by kenny.

    also if you guys find any typo's or errors or just my slang, just lemme know here and then i can correct it :toast:
    Last edited: Sep 24, 2007
  21. panchoman

    panchoman Sold my stars!

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    oh god keaker, i just updated the intro that you sent me, and i started reading the rest and man thats a huge load of info lol, and i got kenny's info on wattage and stuff too man, i gotta move you guys towards the end of the to do list lol, too lazy to go through all the info and then consolidate it and then revamp it lol. so instead i'm going to be adding wile e's stuff on tecs and then maybe work on the first part of the guide, since all the info you guys sent me if like for the second part.
  22. panchoman

    panchoman Sold my stars!

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    to do list for this guide as of today: (probably will process some of these next week)

    - adding info on auxiliary psu's --- done how do i do strikethrough?

    -adding lots of info on wattage and stuff like that.

    - working more on part 1.

    -19 more brands coming out for the brand/oem list, if you need a brand thats not on the guide already, just drop me a pm or post here and i'll do it first cause it'll take a long while before i get all 19 up lol

    the list is sorta in order priority wise lol.
    Last edited: Sep 27, 2007
    Fuse-Wire says thanks.
  23. intel igent

    intel igent New Member

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    nice little tid-bit of info here pancho :toast:

    according to that calc my powerstream520 is still up to task :cool:
  24. Fuse-Wire

    Fuse-Wire New Member

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    just gotta thnk you pancho. thats some guide, think ill have to print it off to go through it again later, top notch!
  25. panchoman

    panchoman Sold my stars!

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    thanks for the compliment guys, i'm working on the guide today so make sure you print it out later :)
    Last edited: Sep 27, 2007

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