Page 1 of 4 123 ... LastLast
Results 1 to 10 of 42

Thread: Hold-up time explained

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. #1
    Join Date
    Jun 2010
    Location
    The Netherlands
    Posts
    5,095
    Thanks Thanks Given 
    367
    Thanks Thanks Received 
    19
    Thanked in
    19 Posts

    Default Hold-up time explained

    Yeah another topic about the hold-up time. Why? Because I got the feeling some really don't understand what it is, what it does and what the problem is.

    What is the hold-up time?
    It's the time in milliseconds that the PSU can work without without getting any power, measured at full load.

    How does it work?
    The primary capacitor of the PSU can store enough energy for the PSU to work some milliseconds after the power is cut.

    How long should it last?
    According to the ATX specification the PSU should deliver at least 17ms full power with voltages still inside the ATX spec.

    But at least 1ms before the output voltages of the PSU go out of spec the PSU should drop the Power OK signal.

    Power OK signal?
    Yes Power OK signal, that's a wire in the 24 pins ATX connector that tells the motherboard that the power of the PSU is stable and that the PC can start or should shutdown.

    What's the problem then?
    Some PSU don't drop the Power OK before the output voltages of the PSU go out of spec. This isn't good because it puts a lot of stress on the components of the PC that are powered by the PSU and now getting voltages that are outside of spec.

    Is it really a problem?
    Well that depends if you experience a lot of problems with power outage where you life, it could be a problem. But if that is the case a UPS is maybe something that you should buy.

    But there is something else you should know!
    Hold-up time is measured at full load! Almost no one loads his of her PSU till full load. And even if someone does, the chance that PSU is working at full load if the power fails, is almost zero.

    So that means that hold-up time actually should last a lot longer in real life conditions. It even could mean that the power OK signal drops before the output voltages go out of spec.

    So it actually isn't a problem?
    For most people not no.

    So please don't make this a huge problem, because it isn't one. It simply isn't done right according to the ATX specification.

    For more information and tests see the reviews from Aris on TechPowerUp and TomsHardware:
    http://www.techpowerup.com/reviews/?...=25&order=date
    http://www.tomshardware.com/articles...power-supplies
    Last edited by -The_Mask-; 05-05-2016 at 06:17 AM.

  2. The Following 11 Users Say Thank You to -The_Mask- For This Useful Post:

    Chipskate (05-05-2016), cypherpunks (12-20-2016), ehume (05-06-2016), Evilution (05-25-2016), GDILord (05-24-2016), Jon Gerow (05-05-2016), marcos669 (05-05-2016), marctronixx (12-23-2016), none77 (05-06-2016), sblantipodi (03-17-2017), sith'ari (05-05-2016)

  3. #2
    Join Date
    Mar 2016
    Location
    Spain
    Posts
    25
    Thanks Thanks Given 
    1
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    Great and straight to the point info, I looked for something like this a few days ago but couldn´t find much

  4. #3
    Join Date
    Jul 2011
    Location
    Germany, Berlin
    Posts
    1,550
    Thanks Thanks Given 
    905
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default

    Here in Germany hold up time is only relevant for professional use. I don't remember any power loss in the last two years here in my flat. In other countries power losses are normal. In my 6 month in spain the power was out at least once per month.

  5. The Following User Says Thank You to Philipus II For This Useful Post:

    sith'ari (05-06-2016)

  6. #4
    Join Date
    Dec 2007
    Posts
    558
    Thanks Thanks Given 
    57
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    Your PG stuff is wrong. Will explain tomorrow.

  7. #5
    Join Date
    Oct 2014
    Location
    Emperor's Retreat/Naboo Moenia
    Posts
    869
    Thanks Thanks Given 
    1,418
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    Quote Originally Posted by -The_Mask- View Post
    .
    .
    .
    So that means that hold-up time actually could last a lot longer in real life conditions. It even could mean that the power OK signal drops before the output voltages go out of spec.
    The magic word is "could".
    "Could" doesn't specify certainty. "Could" means that either it will or it will not !!
    And as i said multiple times in the past, i'm not a person that likes risks, and the 50%-50% chance of the "could" word, is a serious risk percentage in my opinion.
    So, if it 1) "could mean that the power OK signal drops before the output voltages go out of spec.", it also 2) could mean that the Power_OK could drop much much later after the voltages get out of spec!!!
    So the conclusion is that we need even more thorough testing and NOT to abandon them completely and pretend that the issue doesn't exist at all !!!
    CPU:Athlon 64 FX60 (2-cores) 2,6GHz
    Mobo:Asrock 939a785g
    cpu cooler:ArcticFreezer13 CO
    RAM:4 GB DDR 400MHz
    GPU:Asus 750 Ti 2GB
    PSU:Seasonic Platinum 660
    Monitor:Asus VE228HR
    Tower:Coolermaster Elite 430

  8. #6
    Join Date
    Jun 2010
    Location
    The Netherlands
    Posts
    5,095
    Thanks Thanks Given 
    367
    Thanks Thanks Received 
    19
    Thanked in
    19 Posts

    Default

    Quote Originally Posted by sith'ari View Post
    The magic word is "could".
    Changed the first could to should.

    and the 50%-50% chance of the "could" word, is a serious risk percentage in my opinion.
    As I was trying to explain, the chance is probably very small in real life.

  9. The Following User Says Thank You to -The_Mask- For This Useful Post:

    sith'ari (05-05-2016)

  10. #7
    Join Date
    Oct 2014
    Location
    Emperor's Retreat/Naboo Moenia
    Posts
    869
    Thanks Thanks Given 
    1,418
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    Quote Originally Posted by -The_Mask- View Post
    Changed the first could to should.
    As I was trying to explain, the chance is probably very small in real life.
    Oh come on.....!!!
    I can't resist with what you are writing!!! Again, probably doesn't specify certainty, and i'm not a person that likes risks and ....blah blah blah you know the rest !!!
    CPU:Athlon 64 FX60 (2-cores) 2,6GHz
    Mobo:Asrock 939a785g
    cpu cooler:ArcticFreezer13 CO
    RAM:4 GB DDR 400MHz
    GPU:Asus 750 Ti 2GB
    PSU:Seasonic Platinum 660
    Monitor:Asus VE228HR
    Tower:Coolermaster Elite 430

  11. #8
    quest for silence's Avatar
    quest for silence is offline Silencer & heathen relic of a human (™ by OW)
    Join Date
    Sep 2013
    Location
    Italy
    Posts
    3,353
    Thanks Thanks Given 
    1,037
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    Quote Originally Posted by -The_Mask- View Post
    Some PSU don't drop the Power OK before the output voltages of the PSU go out of spec.
    And why then UVP doesn't kick in, in that case? Is it too slow?


    Quote Originally Posted by Philipus II View Post
    In other countries power losses are normal. In my 6 month in spain the power was out at least once per month.
    Italy is much more similar to Spain.
    Best, Luca

  12. #9
    Join Date
    Jun 2010
    Location
    The Netherlands
    Posts
    5,095
    Thanks Thanks Given 
    367
    Thanks Thanks Received 
    19
    Thanked in
    19 Posts

    Default

    Quote Originally Posted by quest for silence View Post
    And why then UVP doesn't kick in, in that case? Is it too slow?
    UVP is mostly set to kick in by a much bigger drop.
    Italy is much more similar to Spain.
    The Netherlands is more like Germany, it almost never happens.

  13. #10
    quest for silence's Avatar
    quest for silence is offline Silencer & heathen relic of a human (™ by OW)
    Join Date
    Sep 2013
    Location
    Italy
    Posts
    3,353
    Thanks Thanks Given 
    1,037
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    Quote Originally Posted by -The_Mask- View Post
    UVP is mostly set to kick in by a much bigger drop.
    1.2V are not enough? So which is the (general) UVP usefulness/goal?


    Quote Originally Posted by -The_Mask- View Post
    The Netherlands is more like Germany, it almost never happens.
    Pares cum paribus facillime congregantur.
    Best, Luca

Similar Threads

  1. Jonny reviews lack the Hold Up Time test.
    By sblantipodi in forum Testing Methodology Discussion
    Replies: 90
    Last Post: 01-05-2018, 06:03 AM
  2. What to do with such screwed hold-up time?
    By Behemot in forum PC Power Supply Discussion
    Replies: 5
    Last Post: 02-12-2017, 12:04 AM
  3. Exploding hold-up time measurement
    By crmaris in forum PC Power Supply Discussion
    Replies: 7
    Last Post: 04-24-2016, 03:47 PM
  4. Sirfa's Hold-up time tricks
    By crmaris in forum PC Power Supply Discussion
    Replies: 33
    Last Post: 03-07-2016, 02:50 PM
  5. Auto-Tune Explained
    By Oklahoma Wolf in forum Off Topic
    Replies: 3
    Last Post: 11-26-2009, 01:46 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •