PC Mech's Tip of the Day - Power Supply Warning.

[bill_bright]

PC Mechanic's Tip of the Day, Power Supply Reliability for 4-19-06 states, "A very rough by easy method of figuring out power supply reliability/strength is, believe it or not, its weight. The more a power supply weighs, generally, the more powerful and reliable it is."

And how does the author justify that remark? By stating, "...the more a power supply weighs, the more "stuff" there is inside."

Stuff?

That's one of the most ridiculous and inaccurate statements about power supplies I have ever heard. More powerful? No! There are several under 350W supplies that are designed for low noise or silent operation and therefore have huge heat sinks, making them quite heavy - easily heavier than many 500W supplies.

Okay, the author said, "very rough method" therefore, I will concede that the heavier of two supplies from the same maker and in the same model line is likely to have a higher wattage rating. So, setting aside his/her "more powerful" argument, let's address the more pertinent remark.

He said, "more reliable!" More reliable? A big and heavy transformer inside a power supply is absolutely NO indication of the "quality" of the windings in that transformer, the tolerances of the regulator circuits, or the quality of the manufacturing process, including soldering and assembly. The weight gives absolutely NO indication of the accuracy or stability of the voltages a supply feeds to the motherboard and video card, or the overall efficiency of the supply. Nor does it give any indication of the quality of the cooling fan(s) used to keep the supply cool. Therefore, there is NOTHING having to do with weight that pertains to "reliability"!

I would MUCH rather have a 450 Watt Antec, Enermax, or ThermalTake supply than a 550W (but heavier) no-name generic knock off. This is one tip that could lead someone away from a quality supply to a cheap no-name inferior supply, which could actually be detrimental to the motherboard (or video card) at worst, cause the motherboard's regulator circuits to work harder age faster, generate more heat, and maybe result in unstable operation.

Bad tip! Bad bad tip!

If you want a "rough" indication of the power - read the label!

[doctorgonzo]

Actually, that tip is quite useful when you are comparing several PSUs with the same rated power. It's going to be less useful when comparing a 450W PSU with a 600W PSU, of course, but I don't think that's what anybody was saying.

It is true that cheaper PSUs use smaller transformers and smaller capacitors, which is why they provide far "dirtier" power. That is why they weigh less than PSUs with quality components. So it's not right to say, as you did, that "there is NOTHING having to do with weight that pertains to reliability". There is something, although as the tip says, it's a rough measure.

[David M]

I would imagine that you are not going to find a high quality PSU that weighs the same as a piece of toast.

On the other hand, I would imagine you could find a garbage PSU that weighs five pounds.

Bottom line? A good quality PSU will have some weight to it. A bad quality PSU could weigh anything.

I think thats what the rule of thumb means and I tend to agree.

I'm sure someone could come up with an example that is contrary to this rule of thumb but thats why they are called "rules of thumb"...because they are not an necessarily an absolute fact 100% of the time but for the most part, they are accurate.

[bill_bright]

Originally Posted by doctorgonzo Actually, that tip is quite useful when you are comparing several PSUs with the same rated power. It's going to be less useful when comparing a 450W PSU with a 600W PSU, of course, but I don't think that's what anybody was saying. It is true that cheaper PSUs use smaller transformers and smaller capacitors, which is why they provide far "dirtier" power. That is why they weigh less than PSUs with quality components. So it's not right to say, as you did, that "there is NOTHING having to do with weight that pertains to reliability". There is something, although as the tip says, it's a rough measure.

Excuse me, but that's just plain wrong! It appears you totally missed the point. There is NO WAY to compare RELIABILITY or QUALITY of a power supply based on weight.

To suggest that someone will get the more reliable power supply by choosing the heavier 400W supply over the lighter 400W supply, is just ludicrous. No disrespect meant here but gee whiz, let's get real. That is not how electronics works.

One PS may have 2 fans. One PS chassis may be made out of aluminum the other steel. One may have more cables. One PS may have ventilation holes punched all over it, the other just a few. One may use thick and heavy PCBs, the other lightweight but stronger PCBs made out of hi-tech composits. The heavier may use many discreet components, the lighter may use more advanced integrated circuitry.

Furthermore, saying "cheaper PSUs use smaller transformers and smaller capacitors, which is why they provide far "dirtier" power" is a totally invalid statement. The "size" of the transformer or capacitors has NOTHING to do with their quality or reliability - the "size" or "weight" does not even have anything to do with how "dirty" the power is under normal loads.

You can NOT assume size and weight - or even power - has ANYTHING to do with quality or reliability, or MTBF rates.

Quality and reliability are determined by the purity of materials used, the precision and tolerances of their construction, and the precision and tolerances of their assembly.

Can you assume a 3.0 liter heavy Chevy engine is of better quality than a 3.0 liter lightweight Toyota engine? Of course not.

[doctorgonzo]

Well, despite your arguments, lots of people who have seen a lot of PSUs in their day will tell you that there is some truth to the tip. The PSUs that are shown as bad in this list tend to be, as a whole, lighter and flimsier than the good PSUs on the list.

I would also disagree with your belief that "the size of transformers and capacitors has nothing to do with quality"...they do have a very real impact on quality. Computer PSUs, being switching power supplies, generate power by rapidly turning on and off power in order to provide the correct voltage and current for the load. The capacitors smooth out the power provided to components, and larger capacitors mean less ripple in the output voltage, which is by definition cleaner power.

[David M]

We are talking a transformer here...not a printed circuit board or some other type of electrical device such as a silicone wafer where weight is irrelevant.

Yes construction, design and materials matter, but so does weight. Do you see transformers on telephone poles that weigh huundreds of pounds performing the same as 20 dollar transformer from Radio Shack?...No, and why? Weight directly relates to the AMOUNT of materials used. You simply cannot push the same amount of current through less copper and iron (transformer materials) than you can a transformer with more copper and iron. You simply need more iron to create the field and more copper to carry the current.

Thats just a basic fact of electronics and physics.

So in essence..... Weight is indeed one of many factors in the construction of a quality transformer and therefore a quality power supply.

Both of you are correct.

[bill_bright]

Wait Doc and David - you both are making invalid assumptions and are trying to apply a general rule of electronics and physics to what the author said. You both are talking and trying to justify your rational by rationalizing that THE PHYSICAL DIMENSIONS of a component determines the current capability of the conductors. If we are talking "identical" materials, then I am not disputing that. But you guys are assuming that ALL 47µf caps from ALL makers are identical shapes, sizes, and weights - you can't do that, just as you can't assume they are of the same quality in materials and workmanship.

Then you guys start talking about current carrying capabilities and watts as though that automatically equates to reliability - you can't do that either. You can't change the givens to suit your arguments. The givens are 5, 12, 3.3 volts, and 350 (in this example) watts. Period. Watts (P)= Current(I) X Electromotive force/volts (E), right? You guys can't change Ohm's law or the givens to suit your arguments.

I am talking reliability on equally "rated" supplies. More current capability does not equate to reliability - UNDER NORMAL OPERATING CONDITIONS. I stress that because the Tip does not discuss the virtues of overhead capabilities of a higher rated supply - that's a whole different topic for which I suspect I we would all be in agreement.

Nor am I disputing that, IN GENERAL, you can determine which PS has a higher wattage RATING by its weight.

But you both through your arguments of current carrying ability are suggesting that higher power equates to higher reliability, and that is just not so either.

My whole issue is being able to determine reliability of one 350W PS over another strictly by weight - NOT THE PC's RELIABILITY, as that was not what the Tip was about - but the PS's reliability - which IS what the author suggests. You can't add all kinds of other factors which he did not present, then call me wrong.

BTW, DOC, the physical size (and therefore weight) of a cap is not the determining factor in its farad rating or necessarily in how it controls ripple. That is determined by the dielectric materials used in the insulator, the size of the gap, the rated voltage, and the the materials used in the plates. The QUALITY of that capacitor is determined by the purity of the materials used, and the construction. You can have two identical (electrically) caps that are quite dissimilar in size and weight, and still be of equal quality and reliability. The physical size (and therefore weight) of a capacitor is not a factor in theory or on a circuit diagram, nor is it a measure of quality or reliability.

David, YOU are talking transformers, I am talking about PC power supplies, which consist of more than just transformers. And you too are talking about current carrying capability - that has nothing to do with quality or reliability of that particular transformer (assuming it is the correct RATING for that application). And certainly, they way line (all actually) transformers are cooled (type of oil, heat sinks used (or not used) on the casing, etc.) has much to do with the size and weight for a given transformer too in a specific application too, as well as its current carrying capability.

If you want to get picky, a 12 inch section of 100% pure copper wire will be a superior conductor, (offer less resistance) be more reliable, and weigh less than a less pure wire of the same dimensions.

[doctorgonzo]

I think you are reading far too much into this. Nobody is talking about current carrying capabilities, or Ohm's law, or anything else.

The tip is a simple observation: In general, the 300W PSUs put out by reliable manufacturers (Antec, Enermax, etc.) are a lot heavier than the 300W PSUs put out by crappy, unreliable manufacturers (DEER). That is generally because Antec PSUs, for example, have much better components than DEER PSUs.

Again, this is not a hard-and-fast rule. But if you hold in one hand a crappy PSU at a particular wattage rating, and hold in your other hand a high-quality PSU at the same wattage rating, the crappy PSU will usually weigh less.

[bill_bright]

With all due respect doc, but when the discussion turns to the size of transformers, and the amount of copper in a conductor, then you certainly are talking about current carrying capabilities, and therefore Ohm's Laws and its derivatives.

I am no spring chicken when it comes to life or electronics technology in general, or computers specifically, having been bitten by the computer bug when I literally walked INSIDE the first computer I ever saw back in the early 70's and saw banks and banks of equipment racks full of diode vacuum tubes!

Yes, a big heavy transformer is normally indicative if big power handling capability. But it is not a sign of quality, nor is it an indication it will last longer than a smaller one. Sorry, it just does not work that way. Especially in this day and age when electronics, all electronics, continues to get smaller, while at the same time, pack a bigger punch.

Perhaps I am putting too much into this tip, but then again, PCMechanics has a reputation of being factual and tips for the day should be just that. While it may be true that Antec puts bigger transformers in their PSs, then again, Antec is known for its overhead and fault tolerance.

BTW - The Antec TP II 550 (a name on your good list) weighs in at 2.3kg while StarTech's smaller PS (a name on your bad list) Startech 480 weighs in at 2.4kg.

(sorry, but DEER does not have a website)

Or the ThermalTake 550 (from the good list) coming in at a measly 2.14kg while the Kingwin 450 (from the bad list) comes in at 5lbs or 2.3kg.

Now it only took me a few minutes to easily come up with those examples so I sure don't know how you concluded that your good list contained heavier PSUs over those on your bad list as that is simply not a fact you could derive from that list! So I can only hope that it was a guess or assumption and not an attempt to obfuscate the facts to justify a weak position.

Now I am sure you can come up with some examples that hold to your theory - but the fact that it is easy to prove one way or the other simply means that you CANNOT use weight as a sign of reliability, or as it now turns out, as even a sign of power!

Now I appreciate your loyalty to PCMech, but the tip, as we now see, was wrong, on both counts!

[Alaron]

Bottom line, the tip was only meant as a rough measure, not a hard rule

For anyone curious about quality power supplies, they can refer to our lists or ask for our recommendations.

End of discussion.

[bill_bright]

Originally Posted by Alaron Bottom line, the tip was only meant as a rough measure, not a hard rule For anyone curious about quality power supplies, they can refer to our lists or ask for our recommendations. End of discussion.

With all due respect to you too, Alaron, but a measure of what? As I demonstrated from that very list you mention, weight cannot be used as a measure of power or reliability - even a "rough" measure - the main points of the tip. Weight as a quality of reliability and power in a power supply is about as useful a measure at fancy looks. I would consider using weight as a measure of quality in a case just a useless - these days, as certainly there are top quality, sturdy aluminum cases from major makers that weigh much less than cases made of steel. And certainly, there some very flimsy cases of all types, including steel, out there too.

And forgive me, but to come in and declare "End of discussion" when few others have had the opportunity to express their views is certainly not what a forum is about.

Now, for me, I am done discussing this as I have proven and verified my point with facts and links to spec sheets from the sites of manufacturers pulled from your very lists. I would have nothing more to add but more examples.

I will agree with you, however, that for those curious about quality power supplies, they can refer to PC Mechs lists, ask for recommendations, and certainly check the web for reviews for specifics models of interest.

[doctorgonzo]

Originally Posted by bill_bright With all due respect to you too, Alaron, but a measure of what? As I demonstrated from that very list you mention, weight cannot be used as a measure of power or reliability - even a "rough" measure - the main points of the tip.

Notice, however, that neither the tip nor anybody else said that weight is ALWAYS indicative of quality, or that a poor PSU will ALWAYS weigh less than a good quality PSU. I and everybody else said things like "usually", "in general", and so forth. I'm not really surprised that you could find some counter-examples; we all know they are out there. That doesn't necessarily change the GENERAL truth of the tip, however.

[Staren]

Originally Posted by bill_bright And forgive me, but to come in and declare "End of discussion" when few others have had the opportunity to express their views is certainly not what a forum is about.

Bill, Alaron is a respected Mod on this forum. He has every right to declare a thread closed when he feels that a discussion is degrading into troll like behavior. Which in my opinion is exactly what is beginning to happen here. Both sides made their case, but when the other side tried to concede to some of your points and leave it at that, you continued to argue and try to 'win' the argument. I know that some forums operate that way, but PCMech does not.

[kstatefan40]

Ok, as the one who entered this tip into the database, and the person in charge of tip QA, it is my responsibility to defend the author's statements to the best of my ability.

1) His "tip" was accurate. I have two power supplies in my hand now. One is a no-name crap 450w PSU, and one is a Xclio 450w PSU. The Xclio is known for reliability, the no-name one died about a month after installed. The Xclio is noticably heavier (likely 4x as heavy) as the no-name brand.

2) Antec, Enlight, Xclio, Thermaltake... all their power supplies are heavy. No-name, or poorly made ones, from my experience, have all been noticably lighter weight.

Now, sure, a company could use a gigantic heatsink to cool the thing down, but from personal experience in the field, I have never seen this to be the case. This method of testing quality without use may not be 100% accurate, but it is common practice in the repair field to use it as a quick-test.

Please keep in mind three things:

• The author of the tip did say that this was a rough method. Rough means not 100% accurate, but still many times useful.
• A tip, by definition, is "an indication of potential opportunity". Tips are generally just useful tidbits that most people may not be aware of. If we didn't want common practices that weren't 100% accurate, we would call it the "Fact of the Day".
• While I appreciate your willingness to help us improve our tips, I do not appreciate the way you bashed it. Constructive criticism without bashing how bad the tip is would be nice. Please keep in mind that this service, as well as this forum, is provided free of charge by PCMech. You have absolutely no right to disrespect a moderator of this forum because of this issue. If you do not like what you see, you are free to leave at any time.

If you have further complaint, please contact me personally by email and I will deal with it.

Thank you for your time,

Tyler Thompson
PCMech.com Public Relations Manager
tyler@pcmech.com

[bill_bright]

Staren - excuse me? The other side tried to concede some of my points? Except where David said that design and materials and construction counted, while in the same sentence and through out the rest of that post, continued on with weight - "the other side" as you put it, continued to argue the "GENERAL truth of the tip" remains the same.

What I see is a new guy coming in, not with just an opinion, but with facts that counter something that was said on "your" forum. And, instead of presenting facts, the regulars gang up on the new guy to attempt to suppress him. That's too bad because no one is perfect. Not even PC Mech. And on other forums I frequent where something stated is proven be incorrect, they acknowledge it.

You are right, other forums do not act this way.
***

Mr Thompson. I concede. The evidence of your two power supplies is overwhelming. Your $45 nearly twenty pound Xclio 450W power supply must truly be awesome, and being the PR guy for the site, I am sure you would not exaggerate.

You folks win. Enjoy your victory. Good day.

[thefultonhow]

This thread has gone on too long already in this vein. I'm going to close it because it is going nowhere but downhill.

bill_bright -- I'm giving you an official warning. You have every right to disagree with the tip, but that's not what I'm warning you about. I'm warning you about your confrontational tone in this thread. There is no reason why you couldn't have disagreed without being inflammatory about it, and PCMech does not tolerate disrespect to its members, as per Rule Two. We love friendly discussion and even corrections, but I don't think you can qualify your behavior in this thread as anything close to "friendly."

You can feel free to PM me or another mod about this issue, but when you do please keep Rule Seven in mind.

[glc]

I'm going to take admin privilege here and post to a closed thread. Mr. Bright, I would encourage you to read this page:

http://www.directron.com/psu.html

How to Choose Computer Power Supply?
Buy a Power Supply by the Pound

- A simple and easy way to estimate the quality of a PC power supply.

Conclusions

This brief study clearly confirms an empirical knowledge: the quality of a power supply can be estimated by its weight. While this is not a true scientific or thorough measurement of the power supply reliability, it is nevertheless a very simple and easy way for ordinary PC users to estimate and compare the quality of a power supply. Directron.com has pioneered this measurement and has now published the weights of all power supplies sold on Directron.com’s web site.

It’s important for the end-users to know the quality of a power supply. The specs of power supplies are simply printed on stickers. Don’t be fooled by them! The stickers can be easily removed and replaced. Even the manufacturers might place a 300W sticker on an otherwise 250W power supply. Once products are shipped it is quiet rare for any private or public entity to go back and verify the specs on the sticker. However, it’s difficult, if not impossible, for a dishonest vendor to alter the weight of a power supply.

By no means is the weight the best way to measure the quality of a power supply. There are other factors one should consider in purchasing a power supply such as wattage, output, brand, price, noise level, and long-term stability. However, to most end-users, measuring the weight may be the only viable method that's widely available.

The large variation in the quality of power supplies with identical wattage rating suggests that an industry agency is needed to rate, confirm, and police the labeling of power supplies to protect the consumers.

Table 2. A guideline to classify the quality of a power supply by its weight (lb).
Low Quality Average Quality High Quality
250W 1.7-2.4 2.4-2.8 2.8-3.1
300W 2.1-2.7 2.7-3.2 3.3-3.8


Based on the above criteria and our general experience in return rates, these are consistently high quality brands on the market: EnerMax, Delta, PC Power & Cooling, Enhance, Antec, CWT, and SPI. These brands are consistently associated with low-eight models: L&C, Deer, Skyhawk, Star, KME, KingStar, and LCT. Our experience shows that the return rates of a low-weight power supply could be as high as twice of those of high-quality ones. How does your power supply measure up?

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There is no excuse for you jumping in here the way you did with your flamethrower all cranked up. Do it again and I promise you that you will be banned instantly. I stand behind the tip as published and intended 100%.

- Forum Administrator -