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Topic: Maximum output I can use from a power supply? (Read 1788 times)

hero member
Activity: 1078
Merit: 502
October 27, 2012, 09:02:56 AM
#29
You really do not want a multi rail power supply, unless it is crowbar protected or VERY expensively designed.
If one of the rails goes down, then your very expensive hardware is toast as the other rails suddenly become biased against the missing rail.

in the case of a -12 +12 , it can become +/- 24v locally in the hardware ,but still look like +/- 12v to the external circuit regulator!!!!




I have a multi rail 1000 watt here and it works.. Turns on.... if you use a certain pci-e cable it shuts off...

if I use it for normal PC use it's fine.....
full member
Activity: 196
Merit: 100
You really do not want a multi rail power supply, unless it is crowbar protected or VERY expensively designed.
If one of the rails goes down, then your very expensive hardware is toast as the other rails suddenly become biased against the missing rail.

in the case of a -12 +12 , it can become +/- 24v locally in the hardware ,but still look like +/- 12v to the external circuit regulator!!!!

legendary
Activity: 1876
Merit: 1000

my rationalization is:   I can buy 4 sets of 'powered' pci cables for 100bucks.
hero member
Activity: 1078
Merit: 502
6 Rails, but they're 38A apiece. I don't see anything wrong with that.

Any PSU I have used with multiple rails has caused me problems.. or died...

Just bad personal experience I guess.
legendary
Activity: 952
Merit: 1000
6 Rails, but they're 38A apiece. I don't see anything wrong with that.
hero member
Activity: 1078
Merit: 502
legendary
Activity: 1876
Merit: 1000
hero member
Activity: 1078
Merit: 502
Well you could get away with a quality 850watter with a max output of 900+ watts.


Quality PSU's are underrated and usually have a higher max output on the 12volt rail.




I agree i underuse my SeaSonics.  I started getting the 650's, cause at least they still have 2 sets of pci wires.. i HATE molex adapters

Me too. I don't mind the single plug ones you get with some of the 7900 series cards, nice and long with a single plug Smiley
legendary
Activity: 1876
Merit: 1000
Well you could get away with a quality 850watter with a max output of 900+ watts.


Quality PSU's are underrated and usually have a higher max output on the 12volt rail.




I agree i underuse my SeaSonics.  I started getting the 650's, cause at least they still have 2 sets of pci wires.. i HATE molex adapters
legendary
Activity: 1344
Merit: 1004
Powering TEN GPU's plus a motherboard/cpu/ram/hard drivefrom a rosewill 1300W lightning all day long, and 6 from a 750W NZXT HALE90. Pretty much all my power supplies are maxxed and are trucking along all day long.
hero member
Activity: 1078
Merit: 502
Well you could get away with a quality 850watter with a max output of 900+ watts.


Quality PSU's are underrated and usually have a higher max output on the 12volt rail.


legendary
Activity: 1876
Merit: 1000
so you will buy a 1200watt PSU instead of a 750watt for fun?  Mining rigs usually only consist of GPU's and a hard drive.

a quality 750watt PSU with 60+ amps on a single 12volt rail will go a long way when you're only running GPU's.


I thought we were here to make money. Smiley

Try to run 5 x 7970's...  i use 2 SeaSonic 750's on one rig. 

Althouth, haveing them clocked at   930/780/0.937, they only pull about 850w at the wall.
hero member
Activity: 1078
Merit: 502
so you will buy a 1200watt PSU instead of a 750watt for fun?  Mining rigs usually only consist of GPU's and a hard drive.

a quality 750watt PSU with 60+ amps on a single 12volt rail will go a long way when you're only running GPU's.


I thought we were here to make money. Smiley
full member
Activity: 196
Merit: 100
Double it!!!!
I.E stay BELOW 50% and have a happy life.


1. Every 10 degrees above 25 degree cent  HALFS the life of electronics.
2. Some days are hotter.
3. Sometimes the device will issue a sudden peak demand on the PSU, the closer you run to the maximum rating the more negative the effect on the internal semiconductors. (ripple increases the more you load towards the max)
4. it is a switched mode power supply, they automatically adjust for the power output required, it is not an iron cored transformer power sucker.

HC

hero member
Activity: 637
Merit: 502
Thanks all for your input. I will use my killawatt and try to stay below 80% of the maximum output.
hero member
Activity: 1078
Merit: 502
Depends on the PSU and your rig setup..


I managed to mine successfully with 4 5800 series cards on a Antec 620watt PSU.


be careful with PSU's with multiple 12volt rails..
full member
Activity: 182
Merit: 100
I have this power supply : OCZ Z series gold 850w

Can I really use the full 850 watts from the 12 volts continuously or I'm asking for trouble?

What is the maximum power I should use if I want to be on the safe side and lowering the chance of breaking it?

It's 80Plus Gold, it's 88% efficient @ 100% load. So it will dissipate 116Watts at max load. It's almost as much a vanilla 80Plus 650W PSU.
Make sure the PSU is well vented at max load, and use a P3 Killawatt to meter the input load, and never exceed 966Watts.

Really? Yes, a 850W PSU that's 88% efficient will pull 966W from the wall at 100%, but he's asking what % he can run at for 24/7 use. You're not going to run ur PSU at 100% for very long. If you're using a kill-a-watt, try to keep the at-the-wall readings below the rated max, in this case 850W.

Some of the PSU reviewers have torture tests, where they put their PSU's in an oven at 50C or some such and load them at 100% for hours. It can be done, but Murphy's law will likely kick your ass. You'd get away with it just "benchmarking", soon as you tried to do something you really needed or wanted to do, it'd cough sparks an hour in.
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