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PSU Guide

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

  1. Mussels

    Mussels Moderprator Staff Member

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    no, you cant combine them.

    putting it simply, if you have four power hungry devices (or groups of devices) in your system using less than the 18A, split evenly over the rails its all good.


    put two of them on the same rail (say, a high powered CPU and a video card or two drawing from the PCI-E slot) and suddenly that one rail might have nowhere near enough power to do its job - while a single (or more powerful dual) rail unit would have no problem.



    multiple rail PSU's arent bad - its when the amperage is so low, that its a bad thing. these 18A rail units just cant handle modern power hungry hardware.
  2. Marclar New Member

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    well don't you use like 2 rails to power modern gpus?
    PS: I'm really confused atm... why would they make weak PSU that's 750w and costs like 100e and lots of people say it can push sli gpus (500 series) easily...
  3. Mussels

    Mussels Moderprator Staff Member

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    let me put it another way.


    you have two wall sockets for electrical power, in two rooms of your house.

    each one can do 100W for the sake of convenience here.


    you can run 200W of devices all you please, so long as its split evenly - but the moment you try and pull 110W of either socket alone, the fuse is going to trip.

    in the case of 18A rails, its 216W. 216W will be fine on a low to midrange system, unless you do something they didnt plan for.

    a good example is that i ran 4870 crossfire on a 700W unit with 4x18A 12V rails. it worked fine, except that i needed to use a molex to PCI-E power splitter... oh yeah, that ran off the same rail as the CPU. under load, this caused the PSU to cut out, turning off the PC.
    i had plenty of power left on the other rails, but the way the PSU was wired i couldnt access that power.

    they can work well, and they can work for years problem free. but i dont see why anyone would ever bother running that risk when you have other choices that do not entail that risk.
  4. Marclar New Member

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    Well That's the thing m8... I live in serbia and dominant brands are CM and Chieftec for PSUs... And i can't see any better PSU that has less rails with more A. I'm investing about 100 euros to buy good and lasting PSU for my current and new PC which ill buy in a year or 2. I also don't plan to have a beast rig which costs 1 to 2k euros... I'm planning on running solid PC spec ill probably get I7 and later on 780 or 760ti depends on how agressive games will be in 2 to 3 years and 750w should be ideal for this combo. Also as you can see with my questions i've never looked on a serious side PSUs and am trying to understand em as much as possible :)
  5. Mussels

    Mussels Moderprator Staff Member

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    you can say 750W, 800W, or 10,000W it means nothing if you cant use those rails.


    if you get a single high end video card, its technically shared over (up to) three sources - some power from the PCI-E slot, some from the two PCI-E plugs. it doesnt matter if you have a 2,000W PSU, since at best, you're stuck with the power from those three sources only.

    i say sources, because you dont really know how they're split inside the PSU - rail 1 could be the 24 pin ATX plug, rail two could be the extra 4/8 pin CPU aux power, with three and four for the PCI-E plugs.

    but then where is the SATA and molex plugs? which rail do you have to avoid overloading to compensate for them?


    if you're after an i7 and a GTX 780, thats not low end. thats high end. take your time, save your money, and find a better unit. corsair, seasonic, enermax, but dont waste your time and money looking for the best of the worst PSU's.
    ChristTheGreat says thanks.
  6. m1dg3t

    m1dg3t

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    This guy prolly has the most info gathered, here is his FAQ list http://www.jonnyguru.com/modules.php?name=NDFAQs Go through the rest of his site to find buying guide's etc....

    TPU's own PSU reviewer crmaris is VERY knowledgeable about PSU's and his reviews are VERY well put together as well so i reccomend going through his review's too ;)
    Mussels says thanks.
  7. Mussels

    Mussels Moderprator Staff Member

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    jonnyguru is miles above my knowledge, you can trust all of his info.
  8. m1dg3t

    m1dg3t

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    Wasn't trying to knock you in any way Mussels, your advice is/was solid :cool:

    Between crmaris & the guru i really don't think you can make a mistake :)

    :toast:
  9. Marclar New Member

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    Wow... thanks guys gonna enjoy educating myself about PSUs :D
  10. Frick

    Frick Fishfaced Nincompoop

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    Chieftec is usually pretty decent for the money BTW. I have one meself and reviews are often "ok".
  11. silkstone

    silkstone

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    Nice write up and very informative.

    I have to disagree with saying all AcBel units you should stay away from. They have some very good write ups on hardwaresecrets but, also, some very bad ones. It really depends on the model. The Cooler master ones made by AcBel are pure crap, but some of the others appear decent enough. Pity there are only a few English reviews on the earlier models and none on the later ones :(
  12. Marclar New Member

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    can any of you suggest a chieftec model that's good and around 100e? :)
  13. Frick

    Frick Fishfaced Nincompoop

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  14. Marclar New Member

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  15. TC-man

    TC-man

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  16. Marclar New Member

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  17. TC-man

    TC-man

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  18. Marclar New Member

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    The ones i see are CoolerMaster, Chieftec, Seasonic(i see very few of their PSUs that are being sold here) Thermaltake. Most PSUs supplied here are CM and Chieftec... Thermaltake and Seasonic dont have many PSUs here :)
  19. Marclar New Member

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    From the looks of it... Looks like Chieftec BPS 750c is the one i will have to go with... :) any1 share some thoughts about it?
  20. TC-man

    TC-man

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    See if you can find a Coolermaster Silent Pro M700W which makes use of an Enhance OEM. Thermaltake has pretty good PSUs, especially the ToughPower series with Channelwell OEMs, but avoid those TR2 or Smart series with HEC OEMs. I guess the 750W Seasonic branded PSUs will be over the 100 Euros budget, but you may find the Seasonic M12II 650W for under 100 Euros, if 650 Watt is enough for you, that is.
  21. Marclar New Member

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    but What about that chieftec BPS 750c?
  22. Marclar New Member

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    can someone share some thoughts about chieftec BPS 750c? and i see there's also thermaltake XT TPX-775M... How better is one from the other also bear in mind that BPS 750c costs about 97euros and TPX 775 costs about 125euros
  23. TC-man

    TC-man

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    I can only find a Tom's Hardware PSU round-up with the Chieftec BPS-750C, Tom's Hardware approved Chieftec's PSU in the round-up. It looks like the BPS-750C makes use of a Channelwell OEM, it may be close to the one of Corsair GS800.


    Well, that Thermaltake Toughpower XT 775 W is a better PSU than the Chieftec BPS-750C, because it make use of a better Channelwell OEM which is more energy-efficient, provides cleaner power, lower noise. I think the Chieftec PSU is more than decent and can deliver the labeled power rating without problem, but if you want something better, then you can consider the Thermaltake XT 775 which got a better design internally which also translates into a higher price.
    Last edited: Apr 16, 2012
  24. Marclar New Member

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    Is it good then?
  25. EarthDog

    EarthDog

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    It depends. Some PSU's even though its multi rail, they really arent, in that there is no OCP on any of the rails so any of the rails can handle the full 12v output. With modern PSU's the situation you describe is rare as most power is on the 12v rail anyway vs old PSU's where it was more so on the 3v/5v rails. ;)

    +1 to Cmaris and especially JG(Oklahoma Wolf and JG himself).

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