Posted by
Hemos
on from the lets'-get-'em-together dept.
CainX writes "A comparison of five power supply units was posted recently. Anandtech has done a more complete review and examined 18 of the newest models in the plus 300 watt range." Power supplies tend to be one of those forgotten, but ever so important parts of machine construction.
Re:How much power is drawn from the wall?
by
wirelessbuzzers
·
· Score: 5, Informative
No, that's a maximum rating. It doesn't draw nearly 400W if you aren't going to use all that, otherwise it would have to dissipate 200W on its own, which it certainly cannot.
-- I hereby place the above post in the public domain.
28 pages? Give me a break.
by
Anonymous Coward
·
· Score: 5, Informative
Design Engineer, Power Supplies, Computers
by
lcsjk
·
· Score: 5, Informative
As one who has spent some 16 years designing power supplies for computers and other devices, I found the article to be very weak in factual information. Power supplies have an actual efficiency of about 75%, and no better than 90%, no matter what brand, Efficiency varies with loading. Quick spin-up on hard drives takes about 5 times as much 12V power as is required for running, but little 5V change. The actual voltage needed by components is not nearly so critical as the amount of noise (ripple and "switching" noise. (These are switching power supplies.) The nearest thing to a noise measurement test was the memory test.
Output regulation is also dependent on the loading of the 5 volts or 3.3 volt outputs. Expect the 12 volts to follow the 5 volts as the processor and MB requires more or less computing power during operation. Some are independent, but most are not.
Things like temperature testing can be very meaningless. Most components are designed for operation at an ambient of more than 70 degrees Celcius. The switching transistors will produce the most heat, but a small capacitor setting downstream in the airflow may be the first long term failure. Probably input to output is the best indication.
Note also that the power supply fan sucks hot air from the PC and sends it over power supply components before exhausting to the outside air.
The one test I found most interesting was the memory test, and although I am not sure of the methods used, the results do indicate overall performance. (Yes, I have also designed memorys and been involved it testing of memory chips with walking ones and zeros and checkerboard patterns etc. Without knowing which row of memory transistors is adjacent to the one being used, pattern testing is basically meaningless except for one word at a time.
A few years ago I took a Sparkle (SPI) power supply and a Fortran power supply apart and the insides were identical - completely. Fortran was about $3 more in hundreds at the time. My guess is that they were made on the same production line. Are they the same or had one just been copied.
The power supply continuous output rating should be the one used when talking about a 300 watt power supply, not the power line rating.
Finally, audible noise. Bigger fans, lower speed, less noise. Fans mounted on the inside instead of near the back panel produce less noise. Fans blowing onto holes instead of through a circular guard produce more noise.
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No, that's a maximum rating. It doesn't draw nearly 400W if you aren't going to use all that, otherwise it would have to dissipate 200W on its own, which it certainly cannot.
I hereby place the above post in the public domain.
Single-page link.
As one who has spent some 16 years designing power supplies for computers and other devices, I found the article to be very weak in factual information.
Power supplies have an actual efficiency of about 75%, and no better than 90%, no matter what brand, Efficiency varies with loading.
Quick spin-up on hard drives takes about 5 times as much 12V power as is required for running, but little 5V change.
The actual voltage needed by components is not nearly so critical as the amount of noise (ripple and "switching" noise. (These are switching power supplies.) The nearest thing to a noise measurement test was the memory test.
Output regulation is also dependent on the loading of the 5 volts or 3.3 volt outputs. Expect the 12 volts to follow the 5 volts as the processor and MB requires more or less computing power during operation. Some are independent, but most are not.
Things like temperature testing can be very meaningless. Most components are designed for operation at an ambient of more than 70 degrees Celcius. The switching transistors will produce the most heat, but a small capacitor setting downstream in the airflow may be the first long term failure. Probably input to output is the best indication.
Note also that the power supply fan sucks hot air from the PC and sends it over power supply components before exhausting to the outside air.
The one test I found most interesting was the memory test, and although I am not sure of the methods used, the results do indicate overall performance. (Yes, I have also designed memorys and been involved it testing of memory chips with walking ones and zeros and checkerboard patterns etc. Without knowing which row of memory transistors is adjacent to the one being used, pattern testing is basically meaningless except for one word at a time.
A few years ago I took a Sparkle (SPI) power supply and a Fortran power supply apart and the insides were identical - completely. Fortran was about $3 more in hundreds at the time. My guess is that they were made on the same production line. Are they the same or had one just been copied.
The power supply continuous output rating should be the one used when talking about a 300 watt power supply, not the power line rating.
Finally, audible noise. Bigger fans, lower speed, less noise. Fans mounted on the inside instead of near the back panel produce less noise.
Fans blowing onto holes instead of through a circular guard produce more noise.