AnandTech Power Supply Test Methodology
by Christoph Katzer on July 12, 2007 12:00 AM EST- Posted in
- Cases/Cooling/PSUs
Conclusion... for now
For many, power supplies are unfortunately still not considered an important component, but this attitude is definitively a mistake. Power supplies deliver the voltage to each and every single component in the PC and make them work. It is the heart of the system and the provided electricity works like blood in the human body. If the delivered electricity is faulty or unstable it can ruin even the greatest high-end rig instantly.
It is important that readers understand the importance of power supplies in today's PCs and we will do our part from now on to deliver the necessary tests. In addition we will explore the manufacturers themselves; good quality starts with a good engineering team that develops upcoming power supplies. We will visit the offices and factories of the manufacturers to show how and where power supplies are made.
When testing power supplies we will pay attention to important aspects of the units. It begins with the design of the PCB and the components used. A power supply might look very good from the outside but the build quality and structure inside could be just rubbish. To help determine the quality of these aspects of a power supply, we will open the test units and analyze the structure and important components on it. These days, power supply efficiency is a very important factor to consider, and it is very dependent on the components that are used. As we will see in the various reviews, better components result in improved efficiency as well as improved results in our other tests.
PCs often play an integral role in today's households. To make having them around more pleasant, it is very important to eliminate - or at least reduce - any noise pollution from the PC. By looking at the temperature of the heatsinks and the exhausted air and by checking the fan speed, we can get a better idea of what design decisions have been made in regards to reducing noise, as well as whether or not the design decisions are effective. Nothing is worse than a noisy power supply that still gets hot!
As a final thought, our tests are based on today's applications and circumstances, but we will also be pushing power supplies to their limits. If a power supply fails during testing, that doesn't necessarily mean it's a truly bad design. Failures can occur for a variety of reasons, and we will be sure to provide a detailed explanation of any failures, why they happen, and what they mean in the broader view of things. For example, we may see a few PSUs that perform extremely well, provided you don't exceed certain loads on some of the voltage rails.
Now that we have introduced our test equipment all that remains is to commence the actual testing and publication of results. Of course, that's not the end of the story, and we will be able to build opinions that will shape our future testing. We took a great deal of time planning, developing, and building our power supply test lab and we are sure it will do what it was built for: to deliver the most accurate and meaningful results possible. Stay tuned as we begin to cover this important area of computer components.
For many, power supplies are unfortunately still not considered an important component, but this attitude is definitively a mistake. Power supplies deliver the voltage to each and every single component in the PC and make them work. It is the heart of the system and the provided electricity works like blood in the human body. If the delivered electricity is faulty or unstable it can ruin even the greatest high-end rig instantly.
It is important that readers understand the importance of power supplies in today's PCs and we will do our part from now on to deliver the necessary tests. In addition we will explore the manufacturers themselves; good quality starts with a good engineering team that develops upcoming power supplies. We will visit the offices and factories of the manufacturers to show how and where power supplies are made.
When testing power supplies we will pay attention to important aspects of the units. It begins with the design of the PCB and the components used. A power supply might look very good from the outside but the build quality and structure inside could be just rubbish. To help determine the quality of these aspects of a power supply, we will open the test units and analyze the structure and important components on it. These days, power supply efficiency is a very important factor to consider, and it is very dependent on the components that are used. As we will see in the various reviews, better components result in improved efficiency as well as improved results in our other tests.
PCs often play an integral role in today's households. To make having them around more pleasant, it is very important to eliminate - or at least reduce - any noise pollution from the PC. By looking at the temperature of the heatsinks and the exhausted air and by checking the fan speed, we can get a better idea of what design decisions have been made in regards to reducing noise, as well as whether or not the design decisions are effective. Nothing is worse than a noisy power supply that still gets hot!
As a final thought, our tests are based on today's applications and circumstances, but we will also be pushing power supplies to their limits. If a power supply fails during testing, that doesn't necessarily mean it's a truly bad design. Failures can occur for a variety of reasons, and we will be sure to provide a detailed explanation of any failures, why they happen, and what they mean in the broader view of things. For example, we may see a few PSUs that perform extremely well, provided you don't exceed certain loads on some of the voltage rails.
Now that we have introduced our test equipment all that remains is to commence the actual testing and publication of results. Of course, that's not the end of the story, and we will be able to build opinions that will shape our future testing. We took a great deal of time planning, developing, and building our power supply test lab and we are sure it will do what it was built for: to deliver the most accurate and meaningful results possible. Stay tuned as we begin to cover this important area of computer components.
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jtleon - Thursday, July 12, 2007 - link
For the most accurate sound level testing, the air temperature around the microphone and the power supply is very VERY important. The microphone must reach steady state temperature and be calibrated at that temperature. The air temperature in the anechoic chamber must be maintained as constant, otherwise the microphone measurements will be off as much as 3-4dB in my experience for a temp delta of only 15°F.Also, no one is interested in the noise PS generates inside the PC case, rather the noise emitted to the exterior of the PC. And beware the air temperature inside the PC is much much higher than the interior PC air temperature. I don't see how your test approach will address these critical issues.
jtleon - Thursday, July 12, 2007 - link
Ooops...I meant to say,And beware the air temperature inside the PC is much much higher than the exterior PC air temperature.
LTG - Thursday, July 12, 2007 - link
This is exactly the high bar I expected from AT and I'm really glad to see you guys do it right.I've always felt that other review sites were missing a lot in this area.
LTG
lsman - Thursday, July 12, 2007 - link
Thanks, looking forward for the reviews. Please don't let it delay (or MIA) like those m-atx or motherboard.It will be more interesting than all those HSF reviews...
Kensei - Thursday, July 12, 2007 - link
A small nitpick... Japan is also 120VAC (actually 100) and uses flat blade plugs. I live in Japan and everthing I brought here from the US works fine. See
http://www.kropla.com/electric2.htm
Martimus - Thursday, July 12, 2007 - link
I used to test power sources and signal sources for variaous automotive components, and I am wondering why you are using a multimeter to measure the output instead of an oscilliscope. You can measure both current and voltage and actually capture the waveform to measure the ripple voltage with a good o-scope. When it comes to analyzing signals, the oscilliscope is a far more valuable tool than a multimeter.just my 2 cents.
acronos - Thursday, July 12, 2007 - link
I'm interested in how the power supply handles electrical noise from the power company. I know most of us have battery backups, but the power supply should do power line noise suppression too. In my area we have brownouts (low voltage), spikes (lightning strikes nearby), and just general noise. I also use computers in a manufacturing environment, which causes significant noise on the power lines.LoneWolf15 - Thursday, July 12, 2007 - link
What you want then, are line conditioners, or a UPS with line-conditioning capability.The most a power supply provides is Active Power Factor Correction, which will clean up things a little, but that's not a subsitute for a UPS with line conditioning, which will solve your issues with brownouts and spikes. This kind of gear would be expensive and bulky to try and add into a power supply; I don't see it happening any time soon.
LoneWolf15 - Thursday, July 12, 2007 - link
Clarification: Not every PSU has Active PFC --a better explanation can be found here:http://www.dansdata.com/gz028.htm">http://www.dansdata.com/gz028.htm
sprockkets - Saturday, July 14, 2007 - link
Yeah very good explanation. Another way of looking at it is I found a site sometime ago that showed the pfc as a 90 triangle to show the relationship.I'm looking for a good test of those fanless power supplies, but again, without a fan it does put a damper in the cooling.