3 ms·

Each switch of a gate causes energy to be expended. When a transistor switches, there is some current flowing and some voltage across the source and sink. That

Each switch of a gate causes energy to be expended. When a transistor switches, there is some current flowing and some voltage across the source and sink. That voltage * current is greater than zero, and therefore requires power. This is opposed to the stable non-switching state where there is no current and therefore no power. So, because each switch consumes the same amount of power, the power consumed is directly proportional to the switching frequency. Double the frequency = double the power. As other posters have alluded, Intel tried to work on the power issue by decreasing the voltage. Unfortunately, they were not able to figure out how to decrease the voltage as they had in the past. With the high power required to run high frequency circuits, cooling would have been more of a problem than could be overcome economically.

baq 10y ago
it's even worse - transistors require more voltage to reliably switch at higher frequencies, e.g. http://images.anandtech.com/reviews/cpu/intel/22nm/powersm.jpg http://images.anandtech.com/reviews/cpu/intel/22nm/powersm.j...
- kec 10y ago
  And to get even more pedantic, it's even worse than that alone implies because switching power increases with the square of voltage. We're also at the point where transistor leakage current matters. All transistors leak a tiny amount of current even without switching. Alone this might only be a few µA, but pack enough of them together on a die and that might add up to hundreds of mA. Combine that with higher voltages so the chip can run at high clock speeds, and the fact that leakage increases with temperature (which will be driven by higher voltages and frequencies), and all of a sudden you have a feedback loop which can cause you to burn a few extra Watts before you've even done anything.

3 ms·

Each switch of a gate causes energy to be expended. When a transistor switches, there is some current flowing and some voltage across the source and sink. That

by DontGiveTwoFlux 10y ago

baq 10y ago
it's even worse - transistors require more voltage to reliably switch at higher frequencies, e.g. http://images.anandtech.com/reviews/cpu/intel/22nm/powersm.jpg http://images.anandtech.com/reviews/cpu/intel/22nm/powersm.j...
- kec 10y ago
  And to get even more pedantic, it's even worse than that alone implies because switching power increases with the square of voltage. We're also at the point where transistor leakage current matters. All transistors leak a tiny amount of current even without switching. Alone this might only be a few µA, but pack enough of them together on a die and that might add up to hundreds of mA. Combine that with higher voltages so the chip can run at high clock speeds, and the fact that leakage increases with temperature (which will be driven by higher voltages and frequencies), and all of a sudden you have a feedback loop which can cause you to burn a few extra Watts before you've even done anything.