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What Power Supplies Are For >> Technical Features from Today’s Power Supplies >> PFC (Power Factor Correction) >> How Big Should The Fan In A Power Supply Be? >> How To Choose The Correct Power Supply >> How To Read And Understand The Label Of A Power Supply >> How Can I Calculate The Total Power Consumption Of My System? >> What Exactly Is Efficiency And How Do I Calculate It? >> Specifications & Certifications >>
What Power Supplies Are ForToday’s PC power supplies are there to deliver electrical power to the components in PC systems. They are a vital part in systems, which is why you should pay attention to some certain details if buying a new unit. There are many advantages from today’s high-end power supplies compared to inferior ones. Cheap power supplies normally lack of important features like safety circuits that protect your PC in case something goes wrong like a lightning strike into the grid, other spikes in the system or short circuits. In addition high-end power supplies offer much higher efficiency which becomes more and more important these days. In most cases they operate much calmer due to higher-end fans. There are also much higher-grade components installed that come with a better reliability in the long term. You therefore have many reasons to look out for higher-grade power supplies if you are searching for a new unit and this is where our COUGAR power supplies come into play. Basic FunctionsPC power supplies are important for the PC since they convert alternating current of 230V (or 110V in the USA for example) into direct current, in our specific case 3.3V, 5V, 12V and -12V. The power supply needs several different circuits for this function which are all inside of the unit. Today’s PC power supplies are all made according to the ATX norm which is a guideline that all different components inside of a PC are functioning together. The ATX norm specifies several rules which the power supply needs to follow. There is for example the a minimum efficiency at a specific load or voltage stability which always needs to stay within a specific area that the PC can actually function without problems. The manufacturer needs to follow these rules when building a power supply to make it possible that components from different vendors work together. The ATX standard is in general downward compatible and only a few connector like for example the 24-pin and 20-pin connector are a bigger different that might bring incompatibilities to the user. It is important that the components in the PC are actually built according to the same ATX specification. Especially motherboards and processors from older standards have it difficult with modern power supplies due to incompatibility. But here lies the big difference between different vendors because each company has its own ideas how to build a power supply. With some power supplies you can find cheap components to lower the production costs and others build power supplies according to very old designs of a much older ATX specification. These units will not be able anymore to power up today’s computers nor even running them stable. Technical Features from Today’s Power SuppliesVoltage Stability Power supplies should have very high voltage stability. You have a stable power supply when the voltage doesn’t leave too far from the originating amount it should have (i.e. 3.3V, 5V or 12V) doesn’t matter which how much load it is running. The higher the load becomes on rails the lower the voltage normally drops. It’s not up to a good power supply to those voltage drops in balance. 12V-Problem Single or Multi Rails? It’s not always good for a manufacturer to follow the rules of the ATX norm though because it could sometimes cause problems with various new technologies such as graphic chips. So it happened not too long ago when a certain graphics chip manufacturer brought out a new chip that needed much more power from the 12V rail than the actual ATX norm allowed. Many companies overruled the specification and built the power supplies according to own rules. In this way there were first single rail 12V power supplies in the market. The problem with demanding graphics cards was solved. The user needs to decide by himself now if he wants to buy a single or multi rail 12V power supply. Reality showed that these graphics chips didn’t need that much power in the end which is why the question of single or multi rail 12V power supplies is somehow unnecessary. Acoustical Noise Acoustical noise is another very important factor to judge today’s power supplies. But it’s also a factor that needs to be taken cautious. If you only look at the acoustic noise of the products you will see that the fan is rotating very low to archive the low level of noise. In this way the fan cannot transport enough or very low amounts of air through the power supply and the heat sinks might not get enough cooling. Components attached to the heat sinks or components that stand in the airflow need to have a certain amount of air to cool down. If the air isn’t sufficient enough the components will decrease their lifetime tremendously. For short term use it doesn’t matter very much but if you are running your PC for several hours per day you need to make sure that all of the components are cooled sufficient. This higher cooling factor means unfortunately that the fan needs to turn faster which also brings unfortunately a higher acoustic noise with it. With our COUGAR power supplies we always strive to get the best performance/cooling factor possible which results in cool heatsinks for a long lasting lifetime paired with a low acoustical noise. Efficiency Today the efficiency of a power supply is very important because there was no other feature developed so much. Today power supplies can have up to 90% efficiency unfortunately not without implementing expensive circuits and components. In any case it’s worth it to look for higher efficiency power supplies when you are in search for a new unit. A few percentages more on the scale can save you money during the years of usage. We prepared some sample calculations on the next pages. To show the customers certain levels of efficiency the 80Plus initiative became quite famous. All of the COUGAR power supplies are certified by 80Plus with the Bronze or Silver level which is why you will instantly save on your electricity bill once you are using our power supplies. Ripple & Noise With all the technical advantages power supplies have today they unfortunately have the disadvantage that their output is always loaded with a periodic and coincidental ripple and noise. The output filter of a power supply must be laid out in such a way that it suppresses the switching frequency, its harmonic waves and high frequency disturbances as effectively as possible. Since switching power supplies cannot react fast to load changes, it must have besides large capacity also low impedance. Since the ATX specification in the version 2.03 it is specified that ripple and noise in the frequency range from 10 Hz to 20 MHz under any circumstance can be over 120mV on the 12V rail and not more than 50mV on the 3.3V and 5V rails. PFC (Power Factor Correction)Active PFC In case of active PFC an upward regulator controller gets implemented into the actual power supply, which creates a sine-wave output. The higher and stabilized operating voltage makes it theoretically possible to reach higher efficiency, which however the usually larger losses of the PFC circuit oppose. The requirements of the capacity of the filter condenser become clearly smaller, however also not too much may be saved here. Otherwise the switching time cannot be intercepted by off-line USVs on battery operation with a power failure as well as short break-downs of mains supply when switching on big consumers like for example a vacuum cleaner. The current ATX specification demands a hold-up time of at least 17ms at full load. Passive PFC When a power supply has passive PFC it will have a large coil included which will be a larger loads at least close to a sine-wave output. The components for passive PFC are mostly larger due to the large coil. Safety FeaturesThat the power supply and the rest of the system is safe from damages all power supplies need to have certain safety features implemented today. These safety functions kick in when there is for example a short circuit in the system or the voltages drop over or under specification. In every power supply there should be many different kinds of safety features and the more there are the better the power supply secures you or the components from damage. COUGAR power supplies have the latest safety features implemented. OCP (Over Current Protection) The OCP is there to protect the rails from overloading current. It makes the power supply stop working once there is too much current flowing through the rails. This is in reality with for example the 12V rail and a written spec of 20 Ampere around 24 to 30 Ampere. The manufacturer uses this small trick from time to time not to get problems with the previously mentioned graphics chips for example. The ATX specification writes that none of the rails can have more than 240VA which is with 12 volts exactly 20 Ampere. Some cheaper power supply offerings don’t even have this safety feature installed. OTP (Over Temperature Protection) The OTP is there to save the power supply from overheating. Power supplies need to work with a temperature up to 50°C. The OTP therefore will kick in a little after that point depending on the vendor. The OTP is very important because if this doesn’t kick in the power supply will die from overheating and not just switching off and wait until most of the heat is gone. COUGAR power supplies will just switch off when overheating and after a certain amount of time you will be able to just switch it on again without any further problems. OVP & UVP (Over/Under Voltage Protection) The OVP protects the components attached to the power supply from a too high voltage output. Too high voltage can damage any component in the PC which is why Intel allows a deviation of up to 5% in the positive or negative direction. This means that for example the 12V rail has an allowed voltage distribution from 11.40V to 12.60V. OPP (Over Power Protection) If you aren’t very familiar with PCs yet you will surely have had an encounter with this safety function before. The OPP is a function that kicks in when the power supply is being overloaded. Overloading is very easy to do. You might have known it just after you bought a new component for your system such as a new graphics card or processor. These kinds of components might use a lot more power than their predecessor which is why the power supply cannot supply enough power. Your PC will either shut down when you start a game for example or not start at all. It’s therefore worth it not to buy only new hardware for better game performance but also having a look if the power supply still fits to the needs of the new system. The 12V rail is mostly used today which is why this rail should be the strongest with much Ampere. Most modern power supplies come with more than one 12V rail to have enough power ready for any circumstance that might come. SCP (Short Circuit Protection) Every rail needs to be protected with a short circuit protection. This function is also vital to those who often work in open PCs and just touch the wrong metal object with the screw driver for example or attached the wrong cable. You see that in any way you always need to be very careful when putting laying your hands on your PC. If you are not sure you should always consult a professional to do these steps for you. If you ever encounter a short circuit inside of your system it should always be protected due to the short circuit protection function. How Big Should The Fan In A Power Supply Be?There is always the question about how big the size of the fan should be in a power supply. Mostly people will answer you shortly like this: the larger the fan the better the performance and the quieter it is. This is unfortunately not entirely true due to the fact that also small 80 mm fans can sufficiently cool a power supply and it doesn’t even need to get too noisy. With today’s power supplies it always depends on the overall cooling concept. Of course larger fans will transport a larger amount of air while rotating slower in comparison with a smaller fan. This means that a larger fan needs fewer rotations to transport the same amount of air compared to a smaller one which makes it much calmer. The advantage of larger fans is that the airflow is easier to reach in all corners of the power supply i.e. reaching the components easier. The disadvantage is that the fan is mounted on the bottom and the air needs to be redirected by 90° to get out in the back. A 80 mm fan doesn’t have this disadvantage because it’s mounted in the back and blow air directly through the power supply to the exit. For this work the fan uses more rotations though which is its disadvantage compare to the larger fan. All COUGAR power supplies come with a 120mm fan (COUGAR power supplies with cable management come with 140mm fan) which is optimized to the heat sinks for a unique cooling concept and best cooling results. How To Choose The Correct Power SupplyThe end-user has a vast amount of power supplies to choose from today. This makes it fairly difficult to find the right product for the own needs. We need to add one more time that it is of utmost importance to find the correct power supply which actually fits to your system. The right power supply will have for example the best possible efficiency, be very calm while operating and best voltage stability. Good power supplies don’t need to be very expensive in any way though because you can calculate your PC’s power consumption and buy the correctly sizes unit for it which is sometimes not a big as you might think. How To Read And Understand The Label Of A Power SupplyTo choose the right power supply you need firstly to understand the label and its content. According to the ATX specification all power supplies need to be marked with a label on which the following content should be mentioned:
The AC input is important for those people that want to use the same power supply in different countries of the world. If you want to use the power supply only in Europe you only need to have 230VAC and you can see a multiple AC input as a free feature. In most European countries the grid power comes with 220-230VAC. Now it’s important to check for the voltage rails since today you will need 3.3V, 5V, 5V Standby, 12V, and -12V rails. If the total power output of the power supply is higher you should make sure it comes with more than one 12V rail to provide enough power to the components. After you know the different rails now it will be important to make sure all of the rails come with the right current to be able to come up with enough power. The current is marked with an A for Ampere on each rail. Both of the important 3.3V and 5V rail should have around 20 to 30 Ampere because in today’s system they make up a very small margin in the total power output. The total combined power of these two rails should be according to the maximum output of the power supply around 130 to 180 watts. More important is the 12V rail today which is why this rail should have at least 18A. Smaller power supplies with less than 400 watts total output can have much less of course. If the power supply does however have more than 500 watts total output it should have either a very strong 12V rail or several ones with up to 20A each. The total combined power of high-performing power supplies should be close to their total output. How Can I Calculate The Total Power Consumption Of My System?To choose the right power supply for your setup you will need to know the rough power consumption of it. You can this easily with a watt-meter on the wall outlet while running your PC. The device will show you the power consumption of the whole system. Make sure you don’t have the monitor as well connected to the watt-meter. The results you see now is unfortunately still not the power consumption of your PC because the power supply still uses a large portion of this for itself. Here comes the efficiency into play which shows how efficient the power supply is converting AC to DC. If you have for example 100 watts written on your watt-meter than the PC will use less for itself because some of the energy is lost during the process of converting. The efficiency is depending on the load of the power supply. You can say that with power supplies today you always reach their best efficiency around medium load which is between 0 and 100% of the total output on the label exactly the middle. If you have for example a 700 watts power supply it will have its roughly best efficiency results at 350 watts. You recognized by now there are several important factors while choosing the right power supply:
To 1. You can search for the power consumption of your components in the internet. Websites for example Provenquality.org offer wattage calculators that are connected to one of the largest databases of components on the internet. You could also search for the TDP (Thermal Design Power) of your components and add them all together. As a result you will get the maximum power consumption possible. But it’s important to know that users not always use the full power of what is possible with their components. It always depends on the program you are running and the settings. Even though when modern graphics cards require for a high current on the 12V rails it doesn’t mean that it is using this all the time. In fact there are only rare moments a normal user will ever reach the maximum power consumption from most of the components. To 2. What are you doing with your PC most of the time? Are you surfing in the internet, writing texts, listening to music, or watching movies? Maybe you are someone who only plays actual high-end shooters with the PC. To find the right power supply you need to know what you are doing with your PC most of the time because the most efficient way of the power supply need to be in exact that load spectrum to get a maximum return on your investment. Surfing, listening to music or writing texts doesn’t load the PC at all and it will be in idle most of the time. If you are running high-end ego-shooter, video encoding or photo editing programs you will use much more resource from your PC. It’s now important to find a good balance in your new power supply. If you own a PC that has a power consumption of 350 watts during demanding applications and you are using this PC all the time only for this purpose then it makes sense for you to buy a 600 to 700 watts power supply just because it will have the best efficiency possible. If you run this PC not under full load most of the times and use it rather to surf in the internet then you can better choose for a lower performing power supply just because it comes with a cheaper price tag. To 3. To be able to choose the right power supply you will need to know the efficiency of the power supply of your choice and how it performs at a certain load. Efficiency curves are displayed most of the times on the package of the power supply but you might rather check it up on review websites that test with professional equipment. You can check the American website AnandTech.com or Planet3dnow.de. if you found the data you need you can take the power consumption of your system and compare it to the efficiency curve of your power supply. What Exactly Is Efficiency And How Do I Calculate It?The efficiency of a power supply is simply calculated with the following formula: Work Output / Work Input x 100 With this formula you divide the delivered power to the system through the incoming power. Multiply this number by 100 and you will receive the percentage of how efficient this power supply is working at that moment. If the power supply works for example with 80% efficiency then 20% is lost mainly through heat to the heatsinks and then to the air. It’s worth it to pay attention to high efficiency products that the loss is as limited as possible. If you are building a new system and you will need a new power supply it makes sense to look for a high performing power supply such as one of the COUGAR series. Today power supplies work in the most efficient way with average load, half of what they should be able to deliver. Do you prefer to play games or surfing on the internet? The following are a few examples to make it clearer. System 1 The power consumption of System 1 is in our case with full load 200 watts. This means that it has with the following different efficiencies the respectively power draw at the wall outlet.
As you can see the difference between the few percentages of efficiency is only marginal. If you compare differences of 6% you can see better results already. If you take higher performing gaming systems you will see that the differences are much bigger as we will be showing with System 2. System 2 The total power consumption of System 2 under full load is 500 watts. The power that the power supply takes out of the wall outlet is the following:
You can see the difference between each percentage is already much bigger than we have seen before. Between 80% and 90% efficiency is a bumming 70 watts difference. Let us take actual prices into our calculation of for example 0.20€ per kW/h. We will have the following results of prices: System 1
System 2
On first sight these prices that need to be paid per hour might not impress too much. Don’t forget that the PC will not run only for one hour but at average maybe 3 hours per day every year then we will get the following prices: System 1
System 2
You see you can save up to 35€ with our sample systems per year. If you are using the PC for several years you can see that you can actually save money if you invest in a high efficiency power supply in the first place. You can recognize high efficient power supplies easily with the 80PLUS certification. Please be aware that 80PLUS tests with an input voltage of 115V. the efficiency with 230Vac is always better so if you are using a high efficient COUGAR power supply you will even have higher efficiency that the 80PLUS report states. Power supplies should not be too overrated when it comes to wattages but you also shouldn’t rate them too close to the actual power consumption of your system either. If your power supply runs all the time under full load the components will age much quicker and it will be louder acoustic noise. If you rate a power supply with the perfect fitting power output it will perform better and more importantly calmer. SpecificationsToday power supplies come with a specific amount of connectors. The amount and length differs from manufacturer to manufacturer. Beside the correct wattage you should also make sure your power supply supports a sufficient amount of connectors to be able to power up your graphics card(s) and motherboard. Modern motherboards are using in most cases a square 4-pin connector with two 12V cables attached to it and two ground lines. The jack sits in most cases close to the CPU socket since it’s supplying the CPU with extra power. Some high-end motherboards even make use of a 8-pin connector that supports double the amount of a 4-pin connector we just described. Don’t mistake this 8-pin connector with the 8-pin PCI Express connector for graphics cards- To ensure this both connectors come with different shapes of the pins. In most cases power supplies come with a sufficient number of connectors for hard drives, optical drives and floppy drives. There are mostly two to five hard drive connectors or optical drives and one or two connectors for floppy drives. If you need more connectors than usual you should check the amount of connectors on your next product of choice. There are mostly more connectors with higher wattage power supplies. The length of the cables and with it the distance of the connectors to the power supply is important if you are running your system in a larger chassis. If the power supply is located in the top part of the chassis the main ATX connectors just needs to be around 50cm long. If it’s located in the bottom you should go for a longer cable harness. The length of cables is very important when it comes to hard drives as well. If your chassis has some hard drives in a distant location in the inside you should make sure your connectors can reach there. VoltagesThere are several different voltages a power supply needs to supply to the PC system. The different voltages are for different components in the PC that have different functions. In older systems the power supply needed very strong 5V and 3.3V rails because the processors at that time needed this voltage for functioning. Today the 12V rail is much more important since it powers up most of the components inside of the system. That’s why modern power supplies need very strong 12V rails. 12V Today the 12V rail supplies to different components such as the processor, the graphics cards and the hard drives. It needs to be very strong because all of the most demanding components rely on this rail. If you have a medium to high-end system you should either have multiple rails with at least 18A. you can recognize a 12V cable on its yellow color. 5V The 5V rail always comes with a red isolation. 5V was very important for older processors but today it plays a rather minor role in the power distribution. There are some hard drives that need this rail and also the motherboard takes larger portions of it still to supply the chipsets and other components on the motherboard. 3.3V The 3.3V rail is also used for the motherboard.you can recognize the rails with their orange isolation. This rail is also not very much needed anymore today. The 5V and 3.3V rail have in today’s systems only up to 100 watts combined power consumption. -5V The -5V rail is in today’s ATX specification not mentioned anymore since it was phased out. A few years ago some audio chips in the motherboard still needed this rail but today this rail is not needed at all anymore. -12V The -12V rail plays also a minor role in the power distribution today. This rail comes with around 0.8A today. 5Vsb The 5V standby rail is an important factor in power supplies today. This rails powers the mainboard in idle state that it’s able to start up once the power button on the chassis has been pushed. Today PC systems have very low standby power consumption but should anyway always be disconnected from the grid once the PC is turned off. ConnectorsATX connector (24-pins) The modern ATX standard comes with a 24-pin connector. Older motherboards that run under the ATX standard version 1.3 will still have only a 20-pin jack. The additional 4 pins were introduced with the version 2.0 of the ATX standard due to increasing power consumption if the PCI-Express slots and its connected graphics cards. From these four pins there are two with 12V rails and two grounding. These two new 12V rails supplies modern graphics cards in the PCI-Express slot with up to 150 watts. The 24-pin connector consists of all the necessary rails that are being used to supply the motherboard and all of its attached components with power. P4 connector (4-pins) In previous years this connector has been called the P4 connector. This was because Intel introduced it for its Pentium 4 processors at that time. Modern processors all need this connector with two additional 12V rails. Older processors or the ones without much power consumption will pull their voltage from the 20-pin connector. EPS connector (8-pins) The EPS-connector was introduced for motherboards in the server and workstation field. It comes with a total of eight rails from which four are with 12V and four with grounding. Modern high-end processors need a lot of power from which the idea resulted to just take two P4 connectors and make an 8-pin out of it. it depends on the processor if you really need these 8-pin connectors but on most modern motherboards this connector is already in use which is why your new power supply should come with this connector as well. In some occasion you will be able to run a processor with a 4-pin connector connected to a 4-pin jack. PCI-Express connector (6-/8-pins) The 6- and 8-pin PCI-Express connector is how the name suggests for modern graphics cards connected to the PCI-Express slot. These connectors are of utmost important for high-end graphics cards because without a properly connected connector the cards will not function. Most of these graphics cards come with a 6-pin connector. If the graphics cards have a higher power consumption they will have a second jack beside the 6-pin jack either with another six pins or eight. SATA connector The SATA connector is rather new and will be needed to power up SATA hard drives and optical drives. There are two versions of the SATA connector. One is coming with and the other comes without additional 3.3V rail connected to it. the additional 3.3V rail not mandatory since it is not mentioned in the specifications but in most cases it is still connected since some hard drives in the past needed this additional voltage. Molex connector (4-pins) The Molex-connector was predecessor to the SATA connectors and does not play a larger role anymore today. It is still kept on power supplies though because some user still run older hard drives or optical drives or want to connect case fans to it. Floppy connector (4-pins) The 4-pin floppy connector is as the name suggests for floppy drives. These drives are rare today since most people use USB drives and only enthusiasts still need this drive for example for a Bios flash. Specifications & Certifications
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