Still so hot!!!!

Kornowski said:
:P Sorry man!



Ok, You're 10c over ambient. I wouldn't consider that bad, remember you're never going to get ambient or sub-ambient temps unless you have some really bad-ass phase cooling or WC'ing.

You've probably experienced lower temps in the past, right? Do you recall if your ambient temperature was around the same? I know you wouldn't have measured it, but you could guess? :P
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i do remember getting high 20's when i first got the processor. ambient was maybe 74F so the temperature was about the same.

but remember i'm not TOO worried about temperatures in the processor, as either way the heat Watts being dissapated are whats affecting my rooms temperature. i've seen the temperature in my room reach 85F while the rest of the house was nice and cool at 74. to me thats insanely hot lol.
 
Yeti said:
Again, where is this extra heat coming from? The temperature adjusts to the heat throughput and the thermal resistance - Q_dot=ΔT/R, where Q_dot is the heat, ΔT is the temperature difference between the CPU and ambient temperature (T_cpu-T_amb), and R is the overal thermal resistance of the HSF. From this equation you can see the only variable you can control is the resistance by changing the HSF. So with a CPU running at steady load (constant Q_dot) and with the ambient air temperature constant, the only thing varied by changing the resistance is the CPU temperature. A CPU with a good heatsink can run at say 35° and that same CPU putting out the same amount of heat can run at 95° with a poor heatsink, assuming it doesn't die first. Heat doesn't get trapped. At steady state there will always be the same amount of heat being transfered; the temperatures just might change. Changing the CPU power consuption (i.e. heat output) means changing the efficiency. Unless you can show that this is happening, I stand by my statements.
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Nobody said that heat gets "trapped," but heat will build up if it is not transferred. A better cooler will draw more heat out of the CPU, thereby keeping it cooler. The heat that it draws out of the CPU will go into the atmosphere. A bad heatsink will draw less heat fromt he CPU therefore putting less into the atmos., and a good heatsink will draw more heat from the CPU, putting more heat into the atmosphere.
 
Cleric9x7 said:
Nobody said that heat gets "trapped," but heat will build up if it is not transferred. A better cooler will draw more heat out of the CPU, thereby keeping it cooler. The heat that it draws out of the CPU will go into the atmosphere. A bad heatsink will draw less heat fromt he CPU therefore putting less into the atmos., and a good heatsink will draw more heat from the CPU, putting more heat into the atmosphere.
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Okay, since you seem to be making statements without any substantiating facts (such as equations) and you're not replying to most of my points (or equations), tell me this - what is the energy balance of the CPU (pick your own electrical power consumption and control volume)? How is energy "retained" in this steady-state system?
 
Cleric7x9 said:
Nobody said that heat gets "trapped," but heat will build up if it is not transferred. A better cooler will draw more heat out of the CPU, thereby keeping it cooler. The heat that it draws out of the CPU will go into the atmosphere. A bad heatsink will draw less heat fromt he CPU therefore putting less into the atmos., and a good heatsink will draw more heat from the CPU, putting more heat into the atmosphere.
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think of it this way. the CPU, HSF and ATMOSPHERE in a line. the heat is being transferred from the cpu to the hsf at 50W. that 50W gets to the HSF but slows down because of inefficiency. the CPU's temp rises as heat backs up, until the efficiency of the heatsink matches what is being put out. now, the processor is at a stable 35C (lets say) and every new bit of heat is being transferred out the HSF into the atmosphere. also once the computer is turned off the tiny bit of residual heat left in the processor and heat sink will dissipate really fast.

Yeti said:
Show me where else the heat will go.
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lol i liked that.
 
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lovely? said:
think of it this way. the CPU, HSF and ATMOSPHERE in a line. the heat is being transferred from the cpu to the hsf at 50W. that 50W gets to the HSF but slows down because of inefficiency. the CPU's temp rises as heat backs up, until the efficiency of the heatsink matches what is being put out. now, the processor is at a stable 35C (lets say) and every new bit of heat is being transferred out the HSF into the atmosphere. also once the computer is turned off the tiny bit of residual heat left in the processor and heat sink will dissipate really fast.


lol i liked that.
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define inefficiency?

id like to add the real steps that come into play here:
cpu
thermal compound
air (or hopefully lack of air)
cpu HSF
air

you see, a crappy application of thermal compound can result in air bubbles and/or other contamination between the cpu and HSF. there is a certain amount of contact for every application...

cpu-hsf-airflow (the most efficient).
cpu-thermal compound-hsf-airflow (will keep the temperatures in-check, but less efficient).
cpu-air bubbles (normally the heat stops there).

the better your application the more heat will get transferred without stopping at air bubbles or having to even transfer through your thermal compound. that's why i lap my cpu's.

unfortunately, air is a great insulator.. which is why water cooling is much more beneficial.. you can transfer a LOT more heat in a smaller amount of time... of course it's also a big pain in the rear... what if your motherboard dies? or your water cooler springs a leak O_O

or what if you simply want to bring your rig to a LAN party! that's good news, but a water cooler would make the trip there a big pain!
 
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i used inefficiency with this definition: Slow in doing the set task but still completing it.

so all those air bubbles and general weak spots in the heatsink will hold a measure of heat but when that heat builds to a certain extent the efficiency of the heatsink will rise to match the incoming heat, but will not rise above that level to dissipate what has already been produced and held back, until the constant source of heat is stopped.
 
Yeti said:
Okay, since you seem to be making statements without any substantiating facts (such as equations) and you're not replying to most of my points (or equations), tell me this - what is the energy balance of the CPU (pick your own electrical power consumption and control volume)? How is energy "retained" in this steady-state system?
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In your equation, does a better heatsink have a higher or lower value for R?

Not that it matters. No equations are needed, its common sense: There's no way of simply getting rid of the heat, it can only be moved from one place to another, if you cool your PC down your room will heat up. But I do not understand the value for R in your equation. Explain R and i will show you mathematically.
 
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what you need is for the heatsink to even out with the cpu's temperature at the fastest rate possible. surface area of the heatsink and airflow mean nothing unless the thermal application was excellent.

think of a pool of water and the water filter. it normally takes the water out in small amount and puts it back in fresh and clean. well, if you plug the intake then it stops cleaning the water and the water gets all dirty. dirty water being an overheated cpu.

also, the faster the rate of the water flow (or heat flow in our case) the cleaner the water, or the cooler the cpu.

lol kind of like my analogy for dual core and quad core cpus:
think of it as two trains (or 4 trains) at 60mph instead of one train at 80mph. you can carry twice the amount of people to their destination in slightly more time, but overall you move more people over time.
but, if you only have one person to move the fastest train would be your best choice.
 
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Cleric7x9 said:
In your equation, does a better heatsink have a higher or lower value for R?

Not that it matters. No equations are needed, its common sense: There's no way of simply getting rid of the heat, it can only be moved from one place to another, if you cool your PC down your room will heat up. But I do not understand the value for R in your equation. Explain R and i will show you mathematically.
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Well it does matter - a good HSF will have a lower resistance. R is the total thermal resistance. From Fourier's Law (Q_dot=k*A*ΔT/L) the resistance is L/(k*A). For convection (Q_dot=h*A*ΔT) the resistance is 1/(h*A). These values are additive, i.e. R_tot = R_conv_1 + R_cond_1 + ... Really, though, I think everyone is caught up on the conservation of energy - the heat produced is constant and equal to the electrical power consumption. This heat doesn't build up in a steady-state system; it is constant by definition - the heat passing through any differential element at any given time is the same. For example, if you are sitting in a cold room at a constant metabolic rate and put a coat on, you don't change the rate that you're body is losing heat (once you and the coat reach a thermal steady state). However, the temperature inside the coat increases due to the increased insulation (increased thermal resistance). Not to be condescending, but common sense isn't a scientific answer.
 
Yeti said:
Well it does matter - a good HSF will have a lower resistance. R is the total thermal resistance. From Fourier's Law (Q_dot=k*A*ΔT/L) the resistance is L/(k*A). For convection (Q_dot=h*A*ΔT) the resistance is 1/(h*A). These values are additive, i.e. R_tot = R_conv_1 + R_cond_1 + ... Really, though, I think everyone is caught up on the conservation of energy - the heat produced is constant and equal to the electrical power consumption. This heat doesn't build up in a steady-state system; it is constant by definition - the heat passing through any differential element at any given time is the same. For example, if you are sitting in a cold room at a constant metabolic rate and put a coat on, you don't change the rate that you're body is losing heat (once you and the coat reach a thermal steady state). However, the temperature inside the coat increases due to the increased insulation (increased thermal resistance). Not to be condescending, but common sense isn't a scientific answer.
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if you could change the material of your skin, or the amount of it exposed to the surface, you could change the rate that your body loses heat, which is exactly what changing a heatsink does...it changes the rate at which the CPU loses heat
 
fade2green514 said:
lol kind of like my analogy for dual core and quad core cpus:
think of it as two trains (or 4 trains) at 60mph instead of one train at 80mph. you can carry twice the amount of people to their destination in slightly more time, but overall you move more people over time.
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not to get off topic, but i think you are confusing multi-threading and multiple cores, they are different.
 
Cleric7x9 said:
if you could change the material of your skin, or the amount of it exposed to the surface, you could change the rate that your body loses heat, which is exactly what changing a heatsink does...it changes the rate at which the CPU loses heat
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No, you would change the the thermal resistance - more or less area would decrease or increase, respectively, the convective resistance. If you can explain anything through thermodynamic/heat transfer equations then please do so.
 
alright buddy, im not getting into equations with you bc i havent taken physics in years. let me ask you this:

are you saying that a better heatsink does not take more heat away from the CPU than a poor heatsink?
 
Cleric7x9 said:
alright buddy, im not getting into equations with you bc i havent taken physics in years. let me ask you this:

are you saying that a better heatsink does not take more heat away from the CPU than a poor heatsink?
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Yes, I am saying, and have maintained since my first post in this thread, that a CPU will output the full amount of heat (electrical power consumption) regardless of the quality (i.e. thermal resistance) of the heat sink. The only change will be the CPU temperature.
 
Yeti said:
Yes, I am saying, and have maintained since my first post in this thread, that a CPU will output the full amount of heat (electrical power consumption) regardless of the quality (i.e. thermal resistance) of the heat sink. The only change will be the CPU temperature.
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i did not ask how much heat the CPU will output. I asked how much heat the heatsink will take from the CPU. you are 100% correct that a CPU will output the same amount of heat no matter what. i am saying that a better heatsink will dissipate more of that heat. i dont see how you can disagree with that...but if you insisit
 
Cleric7x9 said:
i did not ask how much heat the CPU will output. I asked how much heat the heatsink will take from the CPU. you are 100% correct that a CPU will output the same amount of heat no matter what. i am saying that a better heatsink will dissipate more of that heat. i dont see how you can disagree with that...but if you insisit
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Okay, so we agree that the CPU will produce the same amount of heat regardless; that's a start. Then where will any non-dissipated heat go if not transferred through the heatsink? Keep in mind that we are (well, at least I am) considering this a steady-state process.
 
Yeti said:
Okay, so we agree that the CPU will produce the same amount of heat regardless; that's a start. Then where will any non-dissipated heat go if not transferred through the heatsink? Keep in mind that we are (well, at least I am) considering this a steady-state process.
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any non-dissipated heat remains in the CPU, causing the CPU to heat up more. as a scientist (yes i have a master's and working on doctorate, just not in physics), of course i agree that the universe is steady state, but you have no defined the system at all. you are just saying this arbitrary system is steady state. does your system include the air inside and outside of the computer? mine does, and i stated that earlier.

so, non-dissipated heat will remain in the CPU. no matter how good of a heatsink you use, there will always be non-dissipated heat in the CPU; if there wasnt any, the CPU would run at room temperature, and we all know this doesnt happen.

a better heatsink will leave less non-dissipated heat in the CPU (read: dissipate more heat away from the CPU)

this heat has to go somewhere, and it goes into the air in the case. that air is then exhausted from the case, into the air outside of the case, thus heating the air in the room more.
 
Cleric7x9 said:
any non-dissipated heat remains in the CPU, causing the CPU to heat up more. as a scientist (yes i have a master's and working on doctorate, just not in physics), of course i agree that the universe is steady state, but you have no defined the system at all. you are just saying this arbitrary system is steady state. does your system include the air inside and outside of the computer? mine does, and i stated that earlier.

so, non-dissipated heat will remain in the CPU. no matter how good of a heatsink you use, there will always be non-dissipated heat in the CPU; if there wasnt any, the CPU would run at room temperature, and we all know this doesnt happen.

a better heatsink will leave less non-dissipated heat in the CPU (read: dissipate more heat away from the CPU)

this heat has to go somewhere, and it goes into the air in the case. that air is then exhausted from the case, into the air outside of the case, thus heating the air in the room more.
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This will work for any system boundaries including the CPU - the CPU the heatsink and the room will work, the entire computer, PSU, case and all will also work if considering the total power consumption (if your computer uses 400W total, you essentially have a 400W space heater at your feet/on your desk). What you're not taking into account is that it is the potential that builds up. Therefore the temperature will increase not the energy flow, i.e. heat, by the equation Q_dot = ΔT/R. Take, for example, a sphere make of uranium that generates 100W of heat through nuclear decay. If this sphere is encased in some sort polymer insulator, the heat generation will not go up, but the temperature of the uranium sphere will increase.
 
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