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PSU PSU with no casing - pitfalls or an absolute non-starter?

Discussion in 'Hardware' started by DragunovHUN, 11 May 2018.

  1. DragunovHUN

    DragunovHUN I want to change my name but I also don't

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    For a while I've been gearing up to do something nasty and entirely unpractical, and one avenue I'm exploring is to get a 4-500W SFX PSU and ditch the casing and the included fan. My understanding of electricity is very rudimentary, so I wanted to get a sanity check before I find something out the hard way.

    Provided that I can resist the temptation of licking the unit while it's on, and I use standoffs so that I don't ground out the PCB with the PC chassis, is it viable to forego the casing or is it important in terms of shielding to protect either the PSU itself or the rest of the PC from some kind of interference?

    Is there anything else I haven't considered? If I go down this route I'm thinking I would handle the cooling by mounting the PSU board near the case intake fans. I could run these either at 20% minimum PWM or turned off when the PC is idle and then ramping as load increases.
     
  2. edzieba

    edzieba Virtual Realist

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    Downsides:

    - Shock hazard. Not just wandering fingers thinking "I'll just unplug this SATA cable with the machine powered off but plugged in, I'll be careful" but any wiring inside the case could potentially end up next to mains voltage.

    - EMF. The PSU case works to shield the rest of the components from all the electrical noise that a switch-mode power supply emits.

    - No direct cooling control. The PSU wants to actively modulate its cooling as required just like a CPU or GPU does. Removing this and doing a 'best guess' cooling method with a nearby case fan could easily lead to it tripping overtemp protection at inconvenient moments.

    If you want to distribute a couple hundred watts of power supply around the inside of the PC without having to deal with a monolithic cuboid power supply, look at some of HDPLEX's internal AC/DC bricks + DC/ATX converters (or the HDPLEX AC/DCs plus the KMPKT Dynamo system, which is also manufactured by HDPLEX). They can be ganged up in parallel to get the desired wattage, and at their rated loads they only need moderate case airflow to keep cool (with direct cooling they can perform well above their rated loads).
     
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  3. Anfield

    Anfield Well-Known Member

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    If you have some obscure requirements regarding PSU dimensions it might be worth to take a look outside of consumer PSUs, there are some very different shapes around in server PSUs.
    Or what edzieba suggested re HDPLEX etc.

    As for the idea of running a PSU without its case I'd consider any recommendation in favour of doing so grossly irresponsible, the risks are simply not worth it, see post above.
     
  4. DragunovHUN

    DragunovHUN I want to change my name but I also don't

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    That's part of what I was afraid of. Fantastic shout regarding the HDPLEX stuff, i've been digging through their site ever since I saw your post. I've actually seen these when I was looking at the NFC S4 a while back and that may have been part of the inspiration to go naked, but I hadn't considered actually researching one of these.

    Their stuff absolutely aces my size and noise considerations, and heck they even have the ATX blanking plate I was gonna make, but the price is still a little bit steep compared to the low end SFX stuff I've been looking at. I guess that's what I get for going off the beaten path, or perhaps what some would consider the idiot tax.

    Do you reckon I could run a 1080 and a mainstream i7, both with their respective turbo clocks, off of a single 300W internal brick and the 400W DC-ATX part with no issues?
     
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  5. TheMadDutchDude

    TheMadDutchDude Flying Dutchman

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    That would be cutting it far too close. The 1080 has a TDP of 180w and the i7 is either 65 or 95w ... add in a few drives and fans, and you’re at your 100% load limit.
     
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  6. RedFlames

    RedFlames ...is not a Belgian football team

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    IIRC a 1070 is the limit for one of those HDPLEX units, partly as i'm fairly sure it only has one PCI-E connector.
     
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  7. DragunovHUN

    DragunovHUN I want to change my name but I also don't

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    Yeah, looking around people seem to be doing it with 330-350W external bricks but there's still some doubt as to stability on the absolute top end, which I definitely share. Though at the same time getting top power draw out of everything strikes me as something that happens more with synthetic stress tests. Push comes to shove, for another $100 I can add on a 160W brick and a 160W pico-like unit that I can run the motherboard off of, plus a bit of extra cabling to deal with. Two kettle leads coming out the back too, this is certainly getting a bit goofy.

    My 1080 runs off a single 8pin as well. Here's hoping the next couple of generations of cards don't reverse course in terms of efficiency or I'll really be in a pickle.
     
  8. RedFlames

    RedFlames ...is not a Belgian football team

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    I was also thinking of that 3d printed case which has a variant designed to accomodate the HDPLEX psu in lieu of a sfx psu, that could only accomodate a 1070 [though that was purely a dimensions thing, the smallest 1080 was still too big for the case].

    EDIT: The case
     
  9. edzieba

    edzieba Virtual Realist

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    The DC-ATX will handle it without breaking a sweat. The 300W AC-DC can handle a 95W CPU + a 1080 unless you run a 'power vampire' workload like Furmark + Prime95 at the same time, and Word of Larry (HDPLEX engineer) is that overcurrent protection is set at 400W. If you want to OC, then you may need to look at a beefier PSU or actively cooling the HDPLEX supply.

    ::EDIT:: I forgot another option: G-Unique's PSUs. They're a similar concept to HDPLEX, but using 12V supply rather than 19V, and available up to 500W (or more for custom orders). Guryhwa builds them to order and ships them from China, so they're not as 'off the shelf' an option as with HDPLEX (can be a month or so to get the parts in hand) but you can get the exact cable lengths etc that you need.
     
    Last edited: 14 May 2018 at 16:17
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