PSUs 101: A Detailed Look Into Power Supplies

Capacitors Manufacturer Tier List

In the case of polymer caps, all types are considered good for PSU usage due to their ability to withstand higher operating temperatures than their electrolytic counterparts. When it comes to electrolytic caps, since they are hugely affected by increased temperatures caused by heat build-up at the PSU's internals (but mostly by current ripple), the caps made by Japanese manufacturers are the safest and highest-quality choice. This is also why Japanese capacitors are always preferred.

However, there are two problems with using Japanese-made caps: their cost is higher and sometimes there are availability problems. Most PSU factories are located in China, so they have to import the capacitors from Japan, requiring additional time and shipping costs. However, we believe enough Japanese companies have manufacturing facilities in China (along with many Taiwanese manufacturers), so the problem might not be as significant in some cases. Of course, it is still much easier for Chinese PSU companies to acquire caps made by a Chinese factory. Chinese cap companies can offer larger quantities, and if we take into account that in most high-end PSUs only Japanese caps are used, then it is more likely for availability problems to occur with Japanese caps.

The situation becomes even worse when you consider that you cannot order huge quantities of Japanese caps, store them for a prolonged period and then use them, since their performance will be greatly affected. Electrolytic caps should be stored under specific conditions in order to retain their electrolytes, and especially for use in SMPS units, their storage period cannot exceed a specific threshold. If the recommended storage period is exceeded, the capacitors need to be checked one-by-one (including ESR and capacity measurements). In many cases, they need reforming before use in order to avoid operating problems. And since the reforming process takes time and equipment, production costs are further affected.

After some serious reading and gathering of information from various PSU manufacturers and engineers, we would like to note that besides the cap's manufacturing origin, it is crucial to choose the right cap for the specific task you have in mind. For example, if you install a cap with only a 380V rating in the APFC stage, then it will fail much sooner, even if it is of very high quality, since its max voltage is too close to the DC bus voltage of this converter. In addition, as with most products, all cap manufacturers have a portfolio that includes products with differences in performance and expected lifetime. So besides a good manufacturer, you also have to choose caps from the suitable product family with the desired technical specifications for the corresponding application. This, of course, applies not only to caps but to all components used in every electronics device. However, inside a PSU, poor component choices can bring undesired results much faster.

First-Tier Caps

Even the Japanese manufacturers include some mainstream lines in their portfolios, which aren't as good as their top-of-the-line products. So, in addition to the brand, we always take a closer look at the product family and its specifications to better judge capacitor quality and to make a rough estimation of their lifetime. 

All Japanese caps are considered of high quality, and we like to see the following cap brands:

  • Rubycon
  • United Chemi-Con (or Nippon Chemi-Con)
  • Nichicon
  • Sanyo/Suncon
  • Panasonic
  • Hitachi
  • FPCAP or Functional Polymer Capacitor (ex-Fujitsu caps segment, which was bought by Nichicon)
  • ELNA

Besides Japanese manufacturers there are also several US and European vendors that make high-quality capacitors. Probably we won't meet any of the below cap brands inside a consumer grade PSU, at least their electrolytic offerings, but we decided that it still worth mentioning them.

  • Cornell Dubilier (USA)
  • Illinois Capacitor (Currently owned my Cornell Dubilier)
  • Kemet Corporation (USA)
  • Vishay (USA)
  • EPCOS (TDK company, Germany)
  • Würth Elektronik (Germany)

Second-Tier Caps

On this list you will find capacitors made by some of the Taiwanese manufacturers, which often use factories in China. These caps perform well, so they are usually used in mid-level PSUs and sometimes even in high-end units, and they strike a balance between good performance and affordable prices.

  • Taicon (belongs to Nichicon)
  • Teapo
  • SamXon (except GF series which belongs to a lower Tier)
  • OST
  • Toshin Kogyo

Third-Tier Caps

These third-tier capacitors, according to information from various PSU manufacturers and people with knowledge of RMA statistics, along with our own experiences with caps, might not be among the best choices, but are still a grade above the caps that belong to the last category.

  • Jamicon
  • CapXon

Fourth-Tier Caps

This group includes the rest of the capacitor brands. When you see one of these brands in a contemporary PSU, you’ll know that the manufacturer set lower-cost production as a priority instead of reliability over time. We are listing only the popular cap brands that are usually found in low-cost PSUs, but we are well aware that many other low-cost cap brands exist and there is a good chance that you'll find them in non-branded PSU, and even in some branded units.

  • G-Luxon
  • Su'scon
  • Elite
  • Lelon
  • Ltec
  • Jun Fu
  • Fuhjyyu
  • Evercon
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  • Alexis Shaw
    In your list of top-tier capacitor manufacturers you missed out on some of the better american and european manufacturers, while these may not be used on many consumer-grade power supplies they are definitely top-tier and if you were to find them you would be happy. I suggest the addition of at least:
    Cornell Dubilier (USA)
    Illinois Capacitor (Now owned my Cornell Dubilier)
    Kemet Corporation (USA)
    ELNA (Japan)
    EPCOS (TDK company) (Germany)
    Vishay (USA)
    Würth Elektronik (Germany)
  • Aris_Mp
    Thank you very much for the list you provided. I am aware of almost all cap brands that you mentioned but unfortunately so far I found none of them inside a desktop/consumer grade PSU. I will think about it however (and also make a research on these cap brands), if I should include them as well inside my list.
  • InvalidError
    Anonymous said:
    Thank you very much for the list you provided. I am aware of almost all cap brands that you mentioned but unfortunately so far I found none of them inside a desktop/consumer grade PSU.

    There is a very high probability you have seen PSUs with several Kemet capacitors in them. You never noticed them simply because SMD capacitors are too small to carry logos, brand name or even value designations.

    The other brands are mostly found in specialty applications such as lab instruments, industrial machines and high-end audio.
  • Math Geek
    very interesting read. more in depth than i need to know yet for the most part understandable and with careful reading it did not leave me confused.

    nice article.
  • TallestJon96
    I only read 2/3 of it, but it's a good article.

    I basically have committed PC heresy with my cx600m. However I think that I'm in the clear with my 65w CPU and 145w CPU. I'd bet my total power draw is actually below 300w, the supposed highest efficiency point of a PSU.

    As a gamer, not a professional, I think it is better to get low power parts, and get a higher rating than you need, rather than get high power parts and high quality PSUs.

    Additionally, if you compare power consumption of a typical system from today to one from 5 years ago, power draw is considerably lower, with the exception of certain graphics cards. *cough* 390x *cough*
  • powernod
    I decided to sign up at Tom's forum, and the only reason was to state how excellent is Aris's article!!!
    Thanks Aris for this very useful article on behalf of us all who want to learn the basic knowledge for PSUs.
    Haven't finished it yet, but i'm very anxious for it !!!
  • GoZFast
    Very nice article!!! You made me remember my college physics courses lol
  • traumadisaster
    I'm glad there are people dedicated to this but I'm not. I can't even read all of the chapter titles in this article. I disagree with the importance you place on this and all of the references you made to this being crucial knowledge.

    PSU and MB are insignificant to me and I can blindly pick one by reviewing user comments from newegg in about 5 min, and it will last for years. For less than $100 each I'm set for nearly a decade.

    CPU and gfx card now that affects fps and is over $1000, actually the most important part to me.
  • Alexis Shaw
    Anonymous said:
    I'm glad there are people dedicated to this but I'm not. I can't even read all of the chapter titles in this article. I disagree with the importance you place on this and all of the references you made to this being crucial knowledge.

    PSU and MB are insignificant to me and I can blindly pick one by reviewing user comments from newegg in about 5 min, and it will last for years. For less than $100 each I'm set for nearly a decade.

    CPU and gfx card now that affects fps and is over $1000, actually the most important part to me.


    I heartily dissagree, user are not the best way to judge reliability, and a bad powersupply is at fult most of the time there is a hardware issue. Further a power supply should last more than one system build, and in general I keep mine for a decade at a time at least. So an investment in a good power supply is not a waste, and a bad one will kill that precious $1000 GPU or CPU. The demo dart power supply on the motherboard is a similar story, however in general they are of higher quality than a cheap mains supply.
  • Alexis Shaw
    Anonymous said:
    Anonymous said:
    Thank you very much for the list you provided. I am aware of almost all cap brands that you mentioned but unfortunately so far I found none of them inside a desktop/consumer grade PSU.

    There is a very high probability you have seen PSUs with several Kemet capacitors in them. You never noticed them simply because SMD capacitors are too small to carry logos, brand name or even value designations.

    The other brands are mostly found in specialty applications such as lab instruments, industrial machines and high-end audio.


    As well as SMT ceramic capacitors, Kemet makes through hole aluminium electrolytic capacitors. These are of high quality, though not as well known as their SMT capacitors. They also make high quality polymer SMT capacitors that are used as bulk capacitors on the power distribution circuitry on laptops and other devices.
  • ujaansona
    A concise and informative article, written with remarkable effort. As an instrumentation engineer I found it enchanting. Thank you Mr. Aris.
  • Brian Blair
    That's a monster of a PSU. But very very overpriced! I would much rather just buy a Seasonic at that price!
  • nukemaster
    Great writeup.
  • Aris_Mp
    Quote:
    In your list of top-tier capacitor manufacturers you missed out on some of the better american and european manufacturers, while these may not be used on many consumer-grade power supplies they are definitely top-tier and if you were to find them you would be happy. I suggest the addition of at least:
    Cornell Dubilier (USA)
    Illinois Capacitor (Now owned my Cornell Dubilier)
    Kemet Corporation (USA)
    ELNA (Japan)
    EPCOS (TDK company) (Germany)
    Vishay (USA)
    Würth Elektronik (Germany)


    Decide to include them in the article for reference and to show also that besides Japanese caps they are also some good US and German brands. Thanks again for your input!
  • hawkwindeb
    I was told there be no math questions...
    .
    LOL
    .
    Seriously though, very complete article
  • dstarr3
    Quote:
    I'm glad there are people dedicated to this but I'm not. I can't even read all of the chapter titles in this article. I disagree with the importance you place on this and all of the references you made to this being crucial knowledge.

    PSU and MB are insignificant to me and I can blindly pick one by reviewing user comments from newegg in about 5 min, and it will last for years. For less than $100 each I'm set for nearly a decade.

    CPU and gfx card now that affects fps and is over $1000, actually the most important part to me.



    You probably buy cheap hard drives, too.

    Enjoy your ticking time bomb. Because a cheap PSU and cheap motherboard is the quickest and surest way to a total system failure.
  • Quaddro
    Great article !!
    Toms should write more like this..
  • mctylr
    Quote:
    One or more bridge rectifiers fully correct the AC power stream after it passes the EMI/transient filter.


    You mean rectifies. A bridge rectifier converts the AC voltage into DC voltage.
    The name bridge, comes from being a bridge of four (power) diodes. ( image: Source: Play Hookey)
  • IWantDatHammer
    Finally a PSU article! :P
  • Aris_Mp
    I had it rectify and not "correct" but the proof editors changed it. Sorry will fix it ASAP. Of course they rectify and this is why they are called bridge rectifiers after all.