R
RJK
Does anyone use this, or if you like, can it cause any problems ?
....currently it's off in my bios, ...bit wary about switching it on :-?
....pasted from Anandtech :-
"Whenever the OS executes the halt instruction, the CPU enters what is known
as the halt state. Architecturally, what's going on in a halt state is the
clock signal is shut off to the CPU for some period of time. With no clock
signal, none of the logic in the chip will do anything and thus power
consumption is reduced. Performance is also significantly reduced; however,
the halt instruction isn't usually called during application usage, so the
performance aspects of the halt state aren't very important.
The problem with the halt state is that it does nothing to reduce voltage,
only current draw by stopping clocks from going to the CPU. Since Power
varies linearly with both current and voltage (P = I * V), you're
effectively only addressing half of the problem. The Enhanced Halt State, as
Intel calls it, does two things: it reduces the clock speed of the CPU by
decreasing the clock multiplier down to its minimum value (on the EE 965
series, that's 14x, or 2.8GHz), then reducing the voltage. The clock speed
is reduced and then the voltage is dropped, to maintain stability.
Intel insists that the enhanced halt state is a significantly lower power
state than the conventional halt state, thanks to the reduction in voltage
in addition to the reduction in clock speed. While the standard halt state
causes a linear reduction in power, Intel's enhanced halt state causes an
exponential decrease in power, potentially offering better power savings
than the standard halt state. The real world impact obviously depends on
how idle your system happens to be."
regards, Richard
....currently it's off in my bios, ...bit wary about switching it on :-?
....pasted from Anandtech :-
"Whenever the OS executes the halt instruction, the CPU enters what is known
as the halt state. Architecturally, what's going on in a halt state is the
clock signal is shut off to the CPU for some period of time. With no clock
signal, none of the logic in the chip will do anything and thus power
consumption is reduced. Performance is also significantly reduced; however,
the halt instruction isn't usually called during application usage, so the
performance aspects of the halt state aren't very important.
The problem with the halt state is that it does nothing to reduce voltage,
only current draw by stopping clocks from going to the CPU. Since Power
varies linearly with both current and voltage (P = I * V), you're
effectively only addressing half of the problem. The Enhanced Halt State, as
Intel calls it, does two things: it reduces the clock speed of the CPU by
decreasing the clock multiplier down to its minimum value (on the EE 965
series, that's 14x, or 2.8GHz), then reducing the voltage. The clock speed
is reduced and then the voltage is dropped, to maintain stability.
Intel insists that the enhanced halt state is a significantly lower power
state than the conventional halt state, thanks to the reduction in voltage
in addition to the reduction in clock speed. While the standard halt state
causes a linear reduction in power, Intel's enhanced halt state causes an
exponential decrease in power, potentially offering better power savings
than the standard halt state. The real world impact obviously depends on
how idle your system happens to be."
regards, Richard