What PSU would I need for an ITX build?

Discussion in 'Power Supplies' started by MustangSVT, Nov 3, 2012.

  1. MustangSVT

    MustangSVT Lifer

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    I am building up a new system and this time it'll be an ITX.

    Components are, IB 3750k @ 4.5ghz (max). Itx z77 board , 8gb ram, HD6850, 1SSD and 1 HDD.

    I read that I don't need crazy psu at all, would 300watt itx psu's be sufficient?
    I will be using good brands.

    updated: For those that are in similar situations, here is an update.

    Components : 3750k @ 4.4ghz, Asrock itx z77e board, 8gb ram @ 2ghz, HD6850 OC, 1 SSD and 1 HHD, 2 140mm Fans.

    I purchased a TFX PSU. It is 80+ approved 350w (400w max) by Powerstation ( a korean brand). I can't find any review but rating was good and total 44amp from 12v as well. It is high quality (coming from Antec earthwatt 450) and size is about 1/3 of the ATX psu.

    With it all, I have no problem what so ever with using it for past week in both work and gaming.

    I've ran all the benchmarks without problems and it doesnt have problem rendering in vray and various games.

    I really thought you needed a high powered psu these days but I guess things got more efficient. So for 1gpu set ups, I recommend good quality 350w.


    And I really wanted to keep the GEMIN II cpu cooler and Accelero I purchased from ZAP long time ago :), so I built a custom case to keep all the sizes to minimam yet to have a vertical gpu configuration(like Raven). Not finished with details on the case, but so far so good. I am now debating Delid or not to delid... ahhhhh 4.4 @ 1.25v and it maxes around 70c.
     
    #1 MustangSVT, Nov 3, 2012
    Last edited: Dec 21, 2012
  2. kleinkinstein

    kleinkinstein Senior member

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    No discrete GPU? The 3570k max TDP is only 77W. So 300W would be perfect.
     
  3. Smoblikat

    Smoblikat Diamond Member

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    HD6850

    300w should still be fine.
     
  4. MustangSVT

    MustangSVT Lifer

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    really? damn, current systems use less power than before?

    I am currently using c2q
     
  5. Zap

    Zap Elite Member

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    Depends on which "before." Also, most people overestimated power needs, or used crappy PSUs that couldn't actually put out what their label claimed. Also, hardware has evolved to use mostly +12v, and older PSUs didn't have as much power on that voltage but most of the newer and better PSUs do.

    Older socket 1366 CPUs, Core 2 Quads and many of the AMD quad/hex CPUs were really power hungry compared to the 3570K Ivy Bridge. Also, some of the older graphics cards requiring a 6 pin as well as an 8 pin power connector were more power hungry than the current ones that only require two 6 pins. FYI a 6 pin is rated for 75W while an 8 pin is rated for 150W. The PCIe slot is rated for 75W. You can do the math. A Radeon 6850 has, what two 6 pin? So it can pull between 150W and 225W. CPU is 77W (not really, but close enough). HDDs take 5-10W though some older ones peak at 15W. Optical drives and SSDs take a lot less.

    Regarding your ITX build, what case are you using? That will determine which PSU you use.
     
  6. VirtualLarry

    VirtualLarry Lifer

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    Actually, it was the 6870 that has two 6-pin, most 6850 were a single 6-pin. At least that's what I remember.
     
  7. Zap

    Zap Elite Member

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    Hey, you are right. I searched for one and found this card. I looked at the image of the PCB and saw two sets of solder pads. If I had looked at the angled image, I would have seen only a single 6 pin connector. The card probably recycles a 6870 PCB. Thus, it uses between 75W and 150W.
     
  8. MustangSVT

    MustangSVT Lifer

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    Yep my HD6850 uses only 1 6-pin. Its good to know c2q is more power hungry. Then I can reuse my antec 450w although I was looking at smaller form factors.

    I haven't decided on the case yet but It's hard to find an ITX case that has what I'm looking for.

    I want it to have:

    1. Small for ITX mobo and doesn't have extra bulk
    2. Takes full size PCIE card (i'll be reusing hd6850 in this case)
    3. Has full clearance for a tall CPU cooler (same space as atx cases)
    4. has space for just SSD and a HDD, no extra space.
    5. no need for optical drive

    Many of the Lian Li's small cases are great, except they all place psu over the cpu area so I have to use OEM heatsink or low profile ones.

    A case like bitfenix Prodigy is nice except it almost doubles the space I am going to use and is much too large.

    I am thinking about doing a custom build in the end.
     
  9. lehtv

    lehtv Lifer

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    I think you should just forget about the CPU cooler clearance issue. I mean, you can get decent enough cooling with a low profile cooler. Overclocking a CPU so much that it'd need a bulky tower cooler to dissipate heat would not be a good idea in a cramped ITX case anyway. You should limit the 3570K OC to about 4.2GHz which can be done at stock voltage or at most a very small voltage boost.

    Is this too big?

    Cooler Master Elite 120
    Internal 3.5" Drive Bays: 3 (of which two can convert to 2x 2.5" bays)
    USB 3.0 x 1 front port
    80mm + 120mm fans
    ATX PSU support
    Full size GPU support
    9.4" x 8.2" x 15.8"
    Fits a GeminII M4 cooler
     
  10. MustangSVT

    MustangSVT Lifer

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    thanks everyone, update on top!
     
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