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Having Trouble Finding The Right PSU

By Daveskater ยท 20 replies
Oct 9, 2007
  1. Hi, I've been searching around for a bit because i just realised that my current PSU isn't quite good enough for my graphics card :dead:

    What in need is at least 350W (according to the box, i'd rather have at least 380) and 18A on the 12V rail. I've been trying ebuyer.com (british version of newegg ;)) but the closest i've found is an Antec EarthWatts 380 which has 17A on the 12V rail. My current PSU is this CoolerMaster one, it only has 12A so obviously it's not quite up to spec.

    I must say that i'm looking to buy a good PSU to last me a while that's not too expensive but i don't need a 650W or anything like that ;) according to this (link courtesy of Rik) i only need 320W but obviously that's not going to be spot on.

    If anyone can help me find a decent PSU for a good price i will be very grateful :)

    Thanks for reading
  2. Rik

    Rik Banned Posts: 3,814

    Personally, i would go for a 400watt or a 450watt.

    You would then be nowhere near to straining the psu and you would have room for expansion at a later date (for extra hdd's or faster opticals for example).
  3. Daveskater

    Daveskater Banned Topic Starter Posts: 1,687

    thanks for the reply :)

    at the moment i already have 2 hdd's, a cd-rw and a dvd-rw, 5 case fans and a couple of pci cards. my mobo and processor are quite old though so they don't use as much power as a new one. I'll go for 400-450 watts if i need to but i'm having trouble finding anything with 18A.

    i just looked at a Seasonic one and it only had 16A and that was a 435W :(

    edit: i've found an Enermax Noisetaker 420W (on the Enermax website) that has 18A but i can't find anywhere to buy it :(
  4. Rik

    Rik Banned Posts: 3,814

    My advice is to spend as much as you can afford to on a good psu. Cheap ones are often a false economy as they often do damage when they fail.

    Post any links to ones you are interested in and i will happily take a look at them. Provided my pain in the **** isp will stay connected that is.:)
  5. Daveskater

    Daveskater Banned Topic Starter Posts: 1,687

    this is the only one i've found so far but i think it might have been discontinued

    if i come across any more i'll put the link up :)
  6. SNGX1275

    SNGX1275 TS Forces Special Posts: 10,729   +409

    I've got 2 Noisetakers. One Noisetaker, and one Noisetaker II. Aside from one of the fans making a bit of noise (clearly a bad fan) I have no complaints about them. I rarely use the system the original Noisetaker is on anymore (and it is the one with 2 quiet fans) so this weekend I opened them both up to swap fans, they looked like quality builds to me (compared to some cheaper PSU's I've opened up).

    Bottom line: I don't think you can go wrong with an Enermax Noisetaker PSU :)
  7. Daveskater

    Daveskater Banned Topic Starter Posts: 1,687

    yeah i had an enermax once, it was good until i broke it ;)

    i can't remember what one it was now but it was 385W :p

    i'll try to scout around a bit more and find somewhere to buy one because i don't really want to run this psu with my graphics card any more. i'd take the card out but i don't have integrated graphics and i think i may have broken my old graphics card a little bit when i thought i'd mess around and overclock it ;) i only did it because i knew my new card was coming the next day though ;)

    edit: i think i've found a psu *cheers*

    it's in my budget and it has 20A on the 12V rail, plus it's an enermax :D here's a link to the shop page, and this review has a picture of the spec sticker. they even give it a gold award at the end ;)

    sounds like i'll go for that one then i expect
  8. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,443   +36

    This PSU would be a better buy. It gives about 32A on the +12V rails combined so it'd be more than enough for your PC plus it's a little cheaper than the Enermax one. It's of good quality too, so no worries there.
  9. Daveskater

    Daveskater Banned Topic Starter Posts: 1,687

    the antec website says that that psu only has 16A on the 12V rail whereas the enermax one has 20A otherwise i'd be up for saving a couple of pounds ;)
  10. Rik

    Rik Banned Posts: 3,814

  11. Jase123

    Jase123 Banned Posts: 1,012

  12. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,443   +36

    It tells you that the combined power on the +12V rails is 384W. Divide this by 12 and you get 32, which is the total number of amps on the +12V rails combined. Look at the second link in my signature for more details on this.
  13. Daveskater

    Daveskater Banned Topic Starter Posts: 1,687

    i see what you mean by dividing the watts up into 12 etc. however, would the card be receiving the 32A from the motherboard and the additional power connector? if it gets one 12V rail from the mobo and another one from the 2nd rail (on the molex connector) i can understand how it would get the 32A but if it doesn't work like that then i still wouldn't be giving it enough power
  14. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,443   +36

    The PCI Express slot on its own is able to provide 75W to the card. The rest is provided by the power connector. The 32A is the combined wattage on the +12V rails i.e. each rail can carry upto 16A but together they can all carry only 32A. Don't worry about the details, just get the PSU. It's a great one and I'm 100% sure it will work fine with your system.
  15. SNGX1275

    SNGX1275 TS Forces Special Posts: 10,729   +409

    The Trio has 3 12V rails at 16A each, but not all at once. They don't add up directly. Thats why that Enermax has 2 12V rails at 20A each but a combined of 30A.

    My vote is still for the Enermax.

    There is some debate as to whether multiple rails is beneficial at all, unless they are truely seperate I think it is detrimental because you are limiting the amperage any one device can pull.
  16. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,443   +36

    There are very limited instances of truly separate +12V rails. Most of them are fed by the same transformer and the rails are only separated after transformation. The few that do have separate rails have one transformer for each rail, thereby guaranteeing a stable power source. If you're looking for a PSU like that, this fits the bill nicely with a single +12V rail delivering 33A. It's of excellent build quality and on par with (I daresay even better than) the Enermax and Antec PSUs. It's slightly cheaper than both the other PSUs too. All in all, a great combination. :)
  17. Daveskater

    Daveskater Banned Topic Starter Posts: 1,687

    i suppose i should have mentioned this but i've got an agp x4 port for my graphics, will that make a difference?

    actually, a quick question about my current psu. i just checked the box to see if it had dual 12V rails and it says that 12V1 is 10A and 12A2 is 15A. I thought that they were both 12A for some reason :confused:

    if we go by Rage_3K_Moiz's way this should mean that the card is getting 25A but by SNGX1275's way it's probably getting about 17A with my current psu.

    maybe i'm making it harder than it is (tends to run in the family ;)) but i'm slightly confused now :blush:

    what i will say is that i like that you can plug in the cables you need with the enermax, i have a load of sata cables lying around in my case that don't need to be there so that would be a bonus being able to not have them there
  18. SNGX1275

    SNGX1275 TS Forces Special Posts: 10,729   +409

    I don't disagree with Rage's seperate rail talk, thats what I was saying in the last paragraph of my previous reply.

    Onto the amperage question. I based my discussion about 20A + 20A not = 40A based on:

    If you look at the Antec Trio they don't show the combined amperage on the 12V system. But I would guess that since 20 + 20 doesn't equal 40, that 16 + 16 + 16 doesn't equal 48. So, with the Enermax it looks to me like you are going to be able to deliver more power down a single 12V rail than the Antec.

    Since I am not sure how they calculate it I don't know what the Antec does total, but my argument above was that according to the sticker, that Antec is only going to give you 16A down any single 12V rail. The Enermax will do 20A, and since we are concerned about high amp draw from a video card, I thought the Enermax was better. Now if you are running 10 hard drives off of this system, you may want the greater total amperage that the Antec will likely give you.

    Edit: I think you can roughly calculate total amperage down the rails as: (Rail 1 Amp + Rail 2 Amp + ...n)*(1-1/n)
    So in the Enermax case it would be (20 + 20) * (1-1/2) = 30
    I checked on 2 of the Enermax Infiniti PSUs (the 650 and the 720) and they had 52 and 56A respectively over 3 rails. Both PSU's had 28, 28, and 30. If you do my math there you get (28 + 28 + 30) * (1-1/3) = 57.3A. That is fairly close to the 56A on the more powerful one.
    If you do the math for that Antec Trio above its (16 + 16 + 16) * (1-1/3) = 32A

    I'm not sure that what I came up with holds true, I didn't google for an explanation, I just came up with that based on looking at 3 PSUs and their ratings.
  19. Daveskater

    Daveskater Banned Topic Starter Posts: 1,687

    on the antec sticker it says that the max load on 12V1, 12V2 and 12V3 is 32A (it's in small writing under the chart :))

    the only patters i can see between the total aperages on the 12V rails is that you have all of the current on 12V1 + 1/2 of the current on any subsequent rails

    e.g. the antec is 16A, 16A, 16A, so this would work out as 16A + 8A + 8A which = 32A

    same for the enermax, 20A + 10A = 30A

    you could write this as 12V1 + 1/2 12V2 (+ 1/2 12V3) = total current (i trained as an engineer so that's how i think ;))
  20. SNGX1275

    SNGX1275 TS Forces Special Posts: 10,729   +409

  21. Daveskater

    Daveskater Banned Topic Starter Posts: 1,687

    haha how about that ;)

    yeah yours looks more sophisticated, my head isn't working at full capacity tonight because i've had a busy day so i kept it fairly simple :)

    same here, seeing as we both came up with the same thing then we're either both wrong or probably both right. i hope for the latter :D

    i went to college too and i work at the local shop as "the freezer man" :D i'm head of the frozen department but it's not exactly "a career in engineering" as my course tutor put it

    however i have emailed for job and i'm awaiting a reply. i don't want my current boss to find out though because we had a load of people leave for uni so if anyone talks about getting another job he doesn't get so happy ;) lately he's been trying to hide al evidence of available jobs haha, we sell newspapers and there's one called "jobs and careers" and we got one in the staff room - guess who wanted us to put it back ;) he's a good bloke really though and if we wanted to leave he wouldn't stop us, he'd sincerely wish us well
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