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just out of interest: When overclocking, I can increase the vcore to get a faster stable clock speed, but is it the extra speed or the extra voltage that increases the temperature?
What causes cpu heat?
- Thread starter Mike_J_Smith
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I THINK it's do to with the transistors amongst other things within the CPU itself. With a higher clock speed the transistors are being switched on/off faster and this faster change of state means that more heat is produced.
The biggest increase of heat though is by putting more voltage through the cpu.
Something along those lines I think anyway, I would wait for a better answer.
The biggest increase of heat though is by putting more voltage through the cpu.
Something along those lines I think anyway, I would wait for a better answer.
killer_uk said:I THINK it's do to with the transistors amongst other things within the CPU itself. With a higher clock speed the transistors are being switched on/off faster and this faster change of state means that more heat is produced.
The biggest increase of heat though is by putting more voltage through the cpu.
Something along those lines I think anyway, I would wait for a better answer.
yeah, all electrical componants generate heat, cause of resistance, only superconductors don't but then they need to be like -200*C to do that, so the answer to your question is every single thing inside a CPU
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its both.
if you imagine a cpu uses x amount of power per cycle, when you are overclocking you are increasing the cpu speed, or how many cycles it does per second. the more cycles it does, the more power it uses.
as for voltage, thats how much power it uses per cycle (again, x). increase the voltage and the cpu uses more power per cycle.
put them together and you've got a lot more power being used, and virtually of of that power is converted to heat by the cpu. Thats a simple explanation but it works
if you imagine a cpu uses x amount of power per cycle, when you are overclocking you are increasing the cpu speed, or how many cycles it does per second. the more cycles it does, the more power it uses.
as for voltage, thats how much power it uses per cycle (again, x). increase the voltage and the cpu uses more power per cycle.
put them together and you've got a lot more power being used, and virtually of of that power is converted to heat by the cpu. Thats a simple explanation but it works
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cheers. another mystery solved ...
Po = Ps * (Fo/Fs) * (Uo^2/Us^2)
Where Po is the heat output of an overclocked CPU
Ps is the CPU's stock heat output
Fo and Fs are the CPU's overclocked and stock frequencies
Uo and Us are the CPU's overclocked and stock voltages.
In other words, higher speed creates more heat, but higher voltage is more significant.
Where Po is the heat output of an overclocked CPU
Ps is the CPU's stock heat output
Fo and Fs are the CPU's overclocked and stock frequencies
Uo and Us are the CPU's overclocked and stock voltages.
In other words, higher speed creates more heat, but higher voltage is more significant.
That is a rough rule but it's not quite right, it does ~work ish tho
Each transistor drives at least one more gate, in an ideal FET the gate oxide leakage is non existant and the power consumption is given by the capacitence of the gate P = C V^2 F
Where C is the gate oxide capacitence, V the voltage and F is the switching frequency.
In addition to this, in a real device there is the gate oxide (usually to the substrate (ground) and the source (highest PD)) leakage which has increased as process ize has decreased giving rise to a static power dissipation.
This is a for a very simple FET, this is a hugely complex thing, it's so complex that even CPU manufacturers still rely on empirical data in simulation.
Each transistor drives at least one more gate, in an ideal FET the gate oxide leakage is non existant and the power consumption is given by the capacitence of the gate P = C V^2 F
Where C is the gate oxide capacitence, V the voltage and F is the switching frequency.
In addition to this, in a real device there is the gate oxide (usually to the substrate (ground) and the source (highest PD)) leakage which has increased as process ize has decreased giving rise to a static power dissipation.
This is a for a very simple FET, this is a hugely complex thing, it's so complex that even CPU manufacturers still rely on empirical data in simulation.
Mattus said:
An excellent summing up. You will find that the rises in temp due solely to overclocking are usually only a couple of degrees, but once the voltage starts going up it's easy to add ten or fifteen degrees celcius.
M