1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

PSU Using a Flex ATX PSU for overclocking?

Discussion in 'Hardware' started by Goatee, 17 Jul 2015.

  1. Goatee

    Goatee Well-Known Member

    Joined:
    19 Apr 2015
    Posts:
    1,741
    Likes Received:
    663
    Need some advice:

    I'm planning on using the following build for a secondary pc build for some light gaming / web browsing.

    • Z97M-ITX/ac
    • Intel Pentium G3258 (53 W)
    • GPU - currently a GT 740, maybe a 950 in future....... (64 W)
    • SSD
    • Seasonic SS250-SU Flex-ATX PSU - 250 W

    Can I have your thoughts on:
    1. I think the 250W PSU should be sufficient. Thoughts?
    2. Overclocking the CPU and maybe the GPU......
     
  2. mrbungle

    mrbungle Undercooked chicken giver

    Joined:
    20 Sep 2004
    Posts:
    5,304
    Likes Received:
    165
    I'd say a mild oc at stock volts on CPU would be OK, past that I wouldn't.
     
  3. Goatee

    Goatee Well-Known Member

    Joined:
    19 Apr 2015
    Posts:
    1,741
    Likes Received:
    663
    What's that recommendation based on?

    Gut feeling or some logic / formula?
     
  4. Darkwisdom

    Darkwisdom Level 99 Retro Nerd

    Joined:
    27 Aug 2011
    Posts:
    2,675
    Likes Received:
    63
    That PSU is weak, and even seasonic's legendary stability, even a mild overclock is pushing it. That PSU is just not equipped to handle Overclocking properly, being a flex power supply. Putting a graphics card is a bad idea as it has a very weak 12v rail, with maybe not even 20.0a combined across the two rails. If you're set on using this rig, overclocked and with a graphics card (something I assume that you're overclocking at some point) then maybe a better power supply.

    Is there a reason you're set on using a flex-atx PSU? They're expensive to run and ATX PSUs are pretty cheap for a decent one.
     
    Last edited: 18 Jul 2015
  5. TheMadDutchDude

    TheMadDutchDude The Flying Dutchman

    Joined:
    23 Aug 2013
    Posts:
    4,745
    Likes Received:
    522
    I didn't think that was so much a snap as a question. ;)

    I too was wondering about the choice of PSU. What case are you using? Is a normal ATX PSU not viable or something?
     
  6. Darkwisdom

    Darkwisdom Level 99 Retro Nerd

    Joined:
    27 Aug 2011
    Posts:
    2,675
    Likes Received:
    63
    I was thinking that myself. Even with HTPCs, Flex ATX psu's aren't very common. I don't see the need for one in a build like this.
     
  7. Goatee

    Goatee Well-Known Member

    Joined:
    19 Apr 2015
    Posts:
    1,741
    Likes Received:
    663
    There was no sarcasm intended in that question, just a request for more info.

    What you have given is what I was looking for however. Your suggestion is that the 12v rail will be iacking. Looking at the specs it looks like the 12v rail is 18a which I understand should be good for around 200w. Given the stock peak consumption would be around 120w + mobo overheads(30w???) I guess that doesn't leave much room. Is that summary correct?

    In terms of being flex-atx being inefficient, it's bronze rating so I had assumed that would be just as sufficient as any other bronze supply? Am I mistaken?

    I have a homemade case, its got a space for a flex Psu for expandability. I'm currently using a thin board powered from a laptop brick, Measuring the space again I may be able to use a flex with longer length.

    So assuming I got a 400w long flex, do the existing reservations still exist? Is there something about the flex format that I'm missing?
     
  8. Darkwisdom

    Darkwisdom Level 99 Retro Nerd

    Joined:
    27 Aug 2011
    Posts:
    2,675
    Likes Received:
    63
    Flex atx PSUs are normally used in 1U rackmount systems. 400w should power the system plus a 960, but you might have to be careful on the OCing. If it crashes and you get random BSOD/shutdowns, then you're using too much power. If space is at a premium, then a pico PSU is an option; some of them go up to 500w.
     
  9. mrbungle

    mrbungle Undercooked chicken giver

    Joined:
    20 Sep 2004
    Posts:
    5,304
    Likes Received:
    165
    The reason I said keep the volts stock is purely to try and keep the power requirements down, I guess even at stock that system at full load will be 130-150w and that won't give you much of a overhead on the 200w available on the 12v.

    It will handle it no problems if you don't go mad but start overclocking the GPU and the CPU heavily and your eating into that 50w or so overhead.

    I am also going to guess if you push that PSU hard the tiny 40mm fan will go into overdrive, rather you than me :D

    Edit:

    If you don't already have that PSU then there are better ones out there, maybe use a beefier one.
     
  10. Goatee

    Goatee Well-Known Member

    Joined:
    19 Apr 2015
    Posts:
    1,741
    Likes Received:
    663
    That's some really good advice, thank you. As you have gathered the use of a flex spec. was down to space and as I haven't purchased it yet, I still have options.

    The suggestion of a pico is interesting, as I had thought they were even lower powered than a flex. Do you have any suggestions for a suitable pico PSU?
     
  11. Darkwisdom

    Darkwisdom Level 99 Retro Nerd

    Joined:
    27 Aug 2011
    Posts:
    2,675
    Likes Received:
    63
  12. Goatee

    Goatee Well-Known Member

    Joined:
    19 Apr 2015
    Posts:
    1,741
    Likes Received:
    663
    I found similar too, but I would be concerned about the reliability.

    Anyone with any experience of these?
     

Share This Page