Load and PSU temps!!!!

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x1600c

Limp Gawd
Joined
Jun 24, 2004
Messages
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how does the load applied to the psu affect the temps and how do you know when you've pushed your psu to the limit? I've noticed that the my psu temps increased dramatically when I added my 6800 but I was not sure if I've maxed it out
 
well, each supply has a range of efficiency, which varies with the wattage that its actually supplying, so say you have a 100 watt consumption at a 65% efficency (meaning 35% of that 100 watts is being put out as heat or 35 watts of heat) the efficinecy rating will likely change at 200 watts to say 70%
generally there is a sweet spot for efficiency

then there are the basic laws of thermodynamics
as the air temperature increases, the heatsinks are able to transfer less heat
and thus the supply at a certain point will be constrained in the power its able to produce at a given temperature, most supplies are rated at 25C, but the typical operating temperature after exhausting the CPU heatsink at a normal room ambient temperature is likely to be closer to 40C, that can represent as much as a 1\3rd decrease in capacity (overall wattage and amps per rail)
 
is there any good places to look up the relative efficiencys of power supplies?? I have a truepower 430 on back order, just wondering where it will "sweet spot"
 
Ice Czar said:
well, each supply has a range of efficiency, which varies with the wattage that its actually supplying, so say you have a 100 watt consumption at a 65% efficency (meaning 35% of that 100 watts is being put out as heat or 35 watts of heat) the efficinecy rating will likely change at 200 watts to say 70%
generally there is a sweet spot for efficiency

then there are the basic laws of thermodynamics
as the air temperature increases, the heatsinks are able to transfer less heat
and thus the supply at a certain point will be constrained in the power its able to produce at a given temperature, most supplies are rated at 25C, but the typical operating temperature after exhausting the CPU heatsink at a normal room ambient temperature is likely to be closer to 40C, that can represent as much as a 1\3rd decrease in capacity (overall wattage and amps per rail)
Click to expand...

One would think by this point in time the case and power supply manufacturers (often the same company) would have re-thought the whole current design. With CPU’s putting off the amount of heat they do these days and video cards staying right with them we are faced with a lot of heat inside the case. We have a fan to cool the video card, fan(s) cooling the CPU plus the heat of the chipset and ram. Even with decent case ventilation the PSU is expected to become part of the exhaust system. Heat raises, that’s fact of life.

It wouldn’t take a rocket scientist to design a case with the PSU at the bottom with a front to back flow through cooling system. Move the fan locations to where they are actually needed to exhaust heat from the inside of the case. A few ducting options to direct the heat flow to the proper fans etc.

I realize that is an oversimplification of the issue and of course it would mean a bit of an increase in case prices, but, look at what we spend on oversized PSU and HSF combos just to make stuff work as is.

Ok, end of rant ;)
 
kick that case over on its side and you more or less described my rackmount
with the standard 3 x 120mm fans in mid case one of which is force feeding my PSU which is isolated from the mobo with a simple divider the wires pass through
 
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