What is the max draw at WALL of a PSU? 80% of 120% of peak output rating?

[ben8jam]

However, to me, it does make sense that a power supply ran <100% would last longer than a power supply ran at 100%. 

Absolutely. I think the part that is confusing to everyone, is a 750W PSU registering 750W on a Kill-A-Watt is actually only outputting approximately 637W (given say a 85% efficiency rating at that higher draw). To run it at the full 750W output, you would see about 930W on the kill-a-watt (assuming it only runs at a decreased 80% efficiency at max output).

[darkomega69]

However, to me, it does make sense that a power supply ran <100% would last longer than a power supply ran at 100%. 

Absolutely. I think the part that is confusing to everyone, is a 750W PSU registering 750W on a Kill-A-Watt is actually only outputting approximately 637W (given say a 85% efficiency rating at that higher draw). To run it at the full 750W output, you would see about 930W on the kill-a-watt (assuming it only runs at a decreased 80% efficiency at max output).

Maybe it's confusion...or lack of critical thinking.

[philipma1957]

However, to me, it does make sense that a power supply ran <100% would last longer than a power supply ran at 100%.

Absolutely. I think the part that is confusing to everyone, is a 750W PSU registering 750W on a Kill-A-Watt is actually only outputting approximately 637W (given say a 85% efficiency rating at that higher draw). To run it at the full 750W output, you would see about 930W on the kill-a-watt (assuming it only runs at a decreased 80% efficiency at max output).

check out jonnyguru.com

he is pretty much the guy with the numbers.

http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=523

http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story3&reid=523

http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story4&reid=523

above is a review of a corsair hx 1200 plat.

it has a 100 amp 12 volt rail

at hot and cold box tests.

92 amp   is  89% hot  and  89.4% cold.    since we run 24.7  just look at hot numbers
70 amp   is  90% hot  and  90.6% cold.
46 amp   is  92% hot  and  91.8% cold.

he has numbers for hundreds of psu's

I try to pull 70% on my psu's  so 1200 watt dc = 90.5 % efficient or  1200/.905 =  1326 max x 70% = 928.2 watts  at the kwatt meter

look at 1200 x 80% and you get 960 watts 

very close to the same  960 and 928.2 

if the psu was 87.5%  eff  at a 70% dc load  you get

1200/.875 =1371.4285  x .7 = 959.999

which is 960 = 960

So  a  1200 watt psu  on a 70% dc load  with 87.5% eff  is  the exact same as   80% of 1200  or 960 = 960

so  both people would be exactly correct  some of the time. 

[Metroid]

Example, take a 1000 watts psu, if you psu is 90% efficiency gold then it means when your computer is at the wall 1100 watts, it means your psu is using its promised 1000 watts but the thing is, as the psu gets close to 1100 watts at wall, 100%, efficiency drops a little, the best efficiency is at 45% offered. If you want the best efficiency at full load then get a platinum or titanium, best brands are corsair, superflower, evga, seasonic, coolermaster.

[darkomega69]

if the psu was 87.5%  eff  at a 70% dc load  you get

1200/.875 =1371.4285  x .7 = 959.999

which is 960 = 960

So  a  1200 watt psu  on a 70% dc load  with 87.5% eff  is  the exact same as   80% of 1200  or 960 = 960

so  both people would be exactly correct  some of the time. 

Correct me if I'm wrong, but 70% dc load is 70% of 1200w, 840w.

[philipma1957]

if the psu was 87.5%  eff  at a 70% dc load  you get

1200/.875 =1371.4285  x .7 = 959.999

which is 960 = 960

So  a  1200 watt psu  on a 70% dc load  with 87.5% eff  is  the exact same as   80% of 1200  or 960 = 960

so  both people would be exactly correct  some of the time. 

Correct me if I'm wrong, but 70% dc load is 70% of 1200w, 840w.

you are correct.   it is a math game

 if a psu is sending  70% of it 1200 watts   in dc it is 840 watts

but  that is the dc at the end of all the 12 volt cables  attached to mobo/cpu/gpu.

the ac load  at the kwatt meter  would be 840/.875 = 960 watts..


or 840 dc/ 960 ac = 87.5% eff  .

[Gotimour]

if the psu was 87.5%  eff  at a 70% dc load  you get

1200/.875 =1371.4285  x .7 = 959.999

which is 960 = 960

So  a  1200 watt psu  on a 70% dc load  with 87.5% eff  is  the exact same as   80% of 1200  or 960 = 960

so  both people would be exactly correct  some of the time. 

Correct me if I'm wrong, but 70% dc load is 70% of 1200w, 840w.

you are correct.   it is a math game

 if a psu is sending  70% of it 1200 watts   in dc it is 840 watts

but  that is the dc at the end of all the 12 volt cables  attached to mobo/cpu/gpu.

the ac load  at the kwatt meter  would be 840/.875 = 960 watts..


or 840 dc/ 960 ac = 87.5% eff  .

I usually run at 80% of the rated power output to be safe and efficient.