Do 80 Plus PSUs generate less heat?

[bgc99]

Do the 80 Plus PSUs generate less heat at a given load? Also would there be much difference between the different 80 Plus levels of certification?

Thanks,
BGC

 

[BrianTho2010]

The better the 80 plus rating the less heat will be produced at a given load.

For example: a 600 watt non 80 plus power supply that is 75% effecient at a 300 watt load will generate 100 watts of heat waste, whereas an 80 plus platinum 600 watt power supply would be 90 to 91% effecient at a 300 watt load and would generate ~33.3 watts of heat waste.

The numbers scale perfectly with larger or smaller power loads.

Heat output = Load/effeciency - Load

ex: 300/0.90 - 300 = 33.33333

 

[TemjinGold]

The better the 80 plus rating the less heat will be produced at a given load.

For example: a 600 watt non 80 plus power supply that is 75% effecient at 300 watts will generate 75 watts of heat waste, whereas an 80 plus platinum 600 watt power supply would be 90 to 91% effecient at 300 watts and would generate ~28 watts of heat waste.

The numbers scale perfectly with larger or smaller power loads.

Not quite. The non 80 plus at 75% efficiency will generate 100 watts of waste. A platinum at 90% would generate 33 1/3 watts of waste.

 

[BrianTho2010]

Not quite. The non 80 plus at 75% efficiency will generate 100 watts of waste. A platinum at 90% would generate 33 1/3 watts of waste.

updated. forgot my arithmetic.

 

[piasabird]

So how does electricity usage and heate and waste apply to an 80 plus power supply based on percentage of load used. In other words what do you think is the ideal load for a power supply? 50%, 60%, 75% etc. What I am getting at is that I am guessing that the power load is got some kind of curve and based on the location in the curve it may create more heat at some points in the curve based on wattage used, efficiency and rating. So for power supplies do they have heat dissipation and power dissipation curves? I am guessing that it also makes a difference in the amount of power that is being used on different lines and wattages. For instance if your power supply has 2 main lines, putting all the drives on one line may not be a good idea, even though it might make for less clutter inside your case.

So if building an integrated computer what effect does using a motherboard like the Intel DH61AG which is designed for a 19 Volt DC Power Source? This motherboard is more like a Laptop Board.

 

[BrianTho2010]

So how does electricity usage and heate and waste apply to an 80 plus power supply based on percentage of load used. In other words what do you think is the ideal load for a power supply? 50%, 60%, 75% etc. What I am getting at is that I am guessing that the power load is got some kind of curve and based on the location in the curve it may create more heat at some points in the curve based on wattage used, efficiency and rating. So for power supplies do they have heat dissipation and power dissipation curves? I am guessing that it also makes a difference in the amount of power that is being used on different lines and wattages. For instance if your power supply has 2 main lines, putting all the drives on one line may not be a good idea, even though it might make for less clutter inside your case.

So if building an integrated computer what effect does using a motherboard like the Intel DH61AG which is designed for a 19 Volt DC Power Source? This motherboard is more like a Laptop Board.

1. Every power supply has an efficiency curve, not that this is usually publicly available. Most power supplies are most efficient between 40-90% or their rated maximum load. Good 80+ power supplies today will keep excellent efficiency up to 100% load and sometimes even further. The waste heat generated will always go up with higher load so there is no ideal load percentage when looking at waste heat. In my opinion the goal is to find a power supply that will heat peak efficiency under your load conditions and still have good efficiency at idle which is where most system run anyway.

2. Regarding load on different lines: Yes, the combination of load on the 12v, 5v and 3.3v at a certain load wattage will affect the efficiency of the power supply. BUT if you are considering just one molex cable vs another, no that does not matter. The only time you ever have to worry about which cable you are plugging into what is when you have a PSU (power supply) that has true multiple 12v+ lines. Most power supplies that say they have multiple 12v+ lines are in part, or completely lying. Today, nearly all consumer power supplies have one large 12v+ line, even the insane 1200 watt PSU's.

I hope that covered your questions, if not LMK.

 

[amenx]

1. Every power supply has an efficiency curve, not that this is usually publicly available.

I find this a useful site:

http://www.plugloadsolutions.com/80PlusPowerSupplies.aspx

It has all PSUs that have passed 80 plus certification and has downloadable pdf files for each containing efficiency curves and other useful data. Click on manufacturers name for list of PSU models that passed.

 

[nipplefish]

As an example, the fan on my x650 doesn't even run most of the time. It only comes on if I start a game or an encoding job.

 

[munkle]

As an example, the fan on my x650 doesn't even run most of the time. It only comes on if I start a game or an encoding job.

I put my pc at full load and I didn't even see it turn on. (Prime 95, and furmark, x4 955, 6850) Maybe because I have positive flow so there is air being pushed through it anyways.

 

[BladeVenom]

I find this a useful site:

http://www.plugloadsolutions.com/80PlusPowerSupplies.aspx

It has all PSUs that have passed 80 plus certification and has downloadable pdf files for each containing efficiency curves and other useful data. Click on manufacturers name for list of PSU models that passed.

Looks like a nice site.

Anyways to make it simple, around 50% is typically the most efficient, with higher loads generally being more efficient than lower loads.

 

[LiuKangBakinPie]

No. It depends on the circuitry. 80 plus are done at 25 degrees.