LinkBack URL
About LinkBacks
The supposedly guide to the power supply funda
Scaring the woolies out of people with this pic. So I thought I would make it more dramatic and scary using my silly little paint skills and my camera.
Nothing great, but its a shame to run those fine hardware on a stupid psu. Issued in public interest.
Alternate Link to this pic if you cant see it:
http://www.imgx.org/pfiles/8081/untitled.JPG
====
What is a power supply?
In a nutshell, power supply converts AC into DC and distributes power to the power according to the pc's needs. There are 2 types of psu- the first is irrelevant and non feasible for a pc- even for an enthusiast. Second one is the one we use-switching mode power supplies AKA SMPS. I'll try to keep this advice as "non- technical" as possible, but if you cant understand, please make efforts to google it.
Before we continue let me clarify 2 things-
#1. just because a power is a 700 watt based psu which gives a 60 amps- doesnt mean it will consume all of it- If a pc requires less, it will take less or else more. If you buy an overpower psu and your system utilises 1/4 part of its potential, its a waste. As a good friend of mine told- the system should use atleast 75% of the power supplies' potential.
#2. Just because full form of smps is switching mode power supplies- doesnt mean there's a switch behind. If you want to know what do they mean by switching, make some efforts and google for it.
-
What should you expect from this guide?
I will not use any formulas and I will try to prevent any technical jargon as much as possible- but for God's sake make efforts to use google. Even I have a book knowledge. "Wattage = Voltage * Amperage" is something which even a 6th standard school boy knows. We are living in a section of the society run by economics. Very few manufacturers actually tell the truth on the specs on the side panel. Book knowledge is accessible by many, but street smart is something that is is acquired. This is just a guide but a ball in your court. Some people ask me via PM with great fascination about power supply, while there are certain individuals questioning something which is fact. Knowledge is meant to be spread- that is why I am being in number of forums I try to help what I can- but at the end of the day nothing beats research. Besides the ball is in your court- your money your wish.
-
Why think about power supply now?
More systems becomes sophisticated but it will need a proper supply for pc's long term health. In reality- psu is responsible for more than half of the pc hardware problem. After the days of AMD 64 athlon, power supply is the vital part of the system. Till those days, l&c, VIP, ZEBRONICS, intex and some el cheapos like odessey. In those days, zebronics and l&c (now VIP) WERE good power supplies. Then came cm extreme 500w and the way we look at power supplies has changed a bit.
-
What are the problems from using underpowered power supply/el cheapo power supply?
Anything. A low-quality power supply can cause several problems, which are mostly difficult to be solved. A defective or bad-intentioned power supply can lock the PC, can result in hard disk bad sectors, can result blue screen of death errors and random resets and freezings, added to many other problems. There have been cases that spikes have fried southbridge, northbridge and even onboard graphic and sound chips. Hard drive and ram are usually the first victims. People eventually spend 1000-5000 (depending on their system) to get it working. But in reality it works barely but its a damaged wreck. Prevention is better than cure, dont you think?
-
How do you judge a power supply?
Not by watts- change that mentality if you have that. There have been cases that unethical dealers and even idiotic people give away the ones which bundle with silly cases. When you talk about these so called high performance power supply- they say its over exaggerated. Its a fact that dealers will try to sell away things which they have in stock and people have a bad habit of buying anything cheap. They need to learn some new set of words- VALUE FOR MONEY. People with half knowledge of computers claim that an average 800 watt can topple a "high performance" power supply with a rating of 400w. Tell them to wake up and smell the coffee- using half the knowledge is more dangerous than no knowledge at all. Power supply manufacturers over exaggerate- its a marketing gimmick. Most probably it pulls 800w from the socket but it will definatly give theoratical supply of 390w to the pc.
-
Why would an el cheapo rated 800w give only 390w? Where are the rest going to? How do I judge a power supply?
There's something very important called efficiency. Higher the efficiency, lesser the power wasted. As I said before (if you read properly) power supply converts AC into DC. If you want to know what is AC and DC power- make efforts to google. When AC gets converted to DC- heat is produced. Major chunk of power is wasted on this heat. Its a reality that there wont be 100% power conversion for a feasible smps unless something ground breaking is invented. Quality of the pcb circuit board, quality and thickness of cabling, cooling, capacitors and other electric components with a good casing assures proper efficiency. Companies makes big promises but its an inevitable process that a well known pc enthusiast, reviewer and in some cases ethical and knowledgeable dealers will give you proper advice.
In order to get a good enough power supply, you need to make efforts to google and use some common sense. Over the years have passed and the importance of +12v rails have come out. Its always necessary that you proper amps for your system. There An average system can survive with 19 amps on +12v rails.
-
What do you mean +12v rails?
In a nutshell it powers majority of the system through many types of connectors. Here are the following connectors:
Main motherboard connector- in old system its a 20 plug connector- in the new ones, they are 24 power connectors. It powers major chunk of your your motherboard. In most of the new age good performance power supply- 20 pin can be detatched from the 4 pin. That is why many companies call it as 20+4 connectors. But not all companies who say 20+4 connectors necessarily means 20 pin can be split from the 4.
ATX12V connector- Its a 4 pin connector which powers another part of the motherboard. Its also a vital connector and must be connected at all times.
EPS12V connector- Same purpose as the ATX12v connector. But it gives more power which is used by high end motherboards. It has a 8 pin port. Most good reputed power supplies can split EPs 12v connector into 2 atx12v connector. Other either have one EPS 12v connector or atx 12v connector.
There are idiots out there (including so called engineers) who put atx 12v on a eatx12v plug (Note: some motherboards call the 8 pin plug on the mother either mention atx12v or eatx 12v) on the motherboard and expect it to run on full capacity. Its not that you cant do- but its best if you dont.
PCI-E connector- Its a connector which powers your graphic card. Some use 6 pin, some use 8 pin. This is another scenario where you need to do justice to the system. If you are assembling it on your own, make efforts to read the manual. Through some miraculous effort some people manage to connect 8 pin EPS12V connector on a PCI-E plug on the graphic card. This is where people make another great mistake and a possibility of a short circuit increases. For once, make efforts to read the power supply's manual- they are with a power supply for a reason. Some psu manufacturers engrave the type of connectors on the connectors itself. Welcoming for many, but if its not- it doesnt hurt to read a power supply. Many power supply come with multiple pci-e connector. It means that they can power up more than one mid range-to-high end graphic cards. But its recommended if you have atleast 50 proven amps on the +12v rails- or else a burnt power supply will be the last thing in your mind.
4 pin molex- This powers components like dvd writers, hard drives, 4 female pin molex connector based fans, fancy LED/cold cathode lights (used to decorate their system like a christmas tree) and stuff. In case of IDE type drivers, they connect the molex directly. But in case of sata- you need a sata power connector. While the new and proper have direct sata power connector, if you have old you can use molex to sata power converter. I doubt it costs more than 50 bucks, but you need to make sure that you get ample amount of sata power connectors and also molex connectors. Same thing applie for molex to pci-e converter. Majority of the companies gives this as an add-on with their graphic card. I would still recommend the direct ones.
Sata power connector- A welcoming and a useful add-on on new age power supply. They are thin and it connects to sata based drives.
Floppy connectors- Its a smaller sized connector which usually powers up floppy disks. However there are certain type of devices which requires floppy connectors- like sound cards. Asus have sound cards that require extra power. It makes sense than implementing a new type of connector. Something which you always get in standard supplies.
-
What is pfc?
Long story made short- power factor correction. They simply contribute in regulating AC power input in the power supply. The modern ones we get are active pfc- or else they are obsolete and not recommended. If you want to know the difference, best if you meake efforts to google it.
-
How a cooling of a power supply is maintained?
Fans and small heatsinks in certain components inside the psu. Usually the fans on the power supply suck air from inside to outside. Some fans are on the side where the cables come out from and others are on the base- usually with 120mm or even 140mm fan.Certain suck air from out to in and some blow air from in to out. Both are right but based on the pc case. The cases I prefer is where I can mount the powersupply on the base and there are air vents on the bottom. In any blow-suck air scenario fresh air is supplied and vented out- so there's always fresh air coming in and blown out. However there are also top mounted cases. If your room temps is around 27-28 degrees celcius in an average and ambience in the case is around 35 degrees Celcius and the power supply pushes air from inside to out- there's nothing to worry about. But if the air is blown from out to inside the case, there might be some disturbance. Overlockers will have some problems since the hot air from the power supply can interact with the heatsink which will disturb the basic air flow distribution funda.
-
What about dual/multiple rails
Another marketing gimmick and a cost cutting measure. In reality, Dual/multiple +12v rails are nothing but a single +12v output divided from the start inside a psu. Because of this, you do loose some amount of amps and DC output. The reason manufacturers do this is because to save money on capacitors, wiring, pcb board and others which contribute to effiency. If they split rails into 2 extensions, they can degrade the quality of the components used in a power supply. But in reality- users need to remember that only single rail can give out more amps and more DC output compared to multiple rails. Granted- high efficiency power supply with powerful amps on single +12v rails are expensive- but its way better than getting ripped off from fancy named power supply. There are companies which use fancy terminology as +12v1 and +12v2 and call them independent- but they are not. Most probably sata/Molex connectors are on a separa wire from the 24 pin Manufacturers also blind users by calling dual rails as sli/crossfire capable however just distribute equal number of pci-e connector on the +12v extensions. But in reality single rail can have dual/multiple pci-e. There 18amps on first +12v rail and 18 amps on +12v rail does not mean 36 amps- it just means you are just getting 18 amps.
-
So the money that I pay is only for the power supply?
Nope. You also pay for the power cable as well. Some provide really good power cable for the power supply which has a blow fuse on the socket itself. If they are damaged due to a spike during power distribution- they will prevent. Note that the blow fuse on the surge protectors and on the power supply's power cable (if it has) will help only to prevent- not stop- any unexplained spike in power distribution. Sleeving and wire quality is also pretty important.
-
Why do companies rip people off by putting fancy wattage
I advise people- I dont work for manufacturers. Some small manufacturers pass under the scanner. Some manufacturers claim that it s a theoratical wattage calculation that us pulled from the power socket at maximum load and not the theoratical wattage on the DC output power so they get away from potential lawsuit. However not all are cheaters- some are very conservative in putting the wattage chap. This is where you need to learn to do research- nothing beats google....yet.
-
What about watts calculator- are they recommended?
They calculate either maximum, average or minimum output- that's why calculations vary from one watts calculator to another. So it depends on the calculators you use. Besides the watts that are calculated are accurate. Mathematically they are, but you need to acknowledge that power supply will only pull more power from the socket if it needs to. If the system is idle- it takes low power- if you are using cpu or gpu intensive based programs, it will pull out more power.
-
But I have been using el cheapos for a long time- why should I make the change now?
I would suggest to read the whole guide properly. Systems always change so certain precautions are needed. If you open your improper power supply, dont be suprised if you see some capacitors start to look like that picture. If you do, consider yourself lucky that your whole precious investment didnt come up in smoke.
If people have any questions, please feel free to ask me :-D
Reply With Quote
Originally Posted by prasannaganesh 
