On Wed, Aug 4, 2010 at 6:14 AM, Xi Shen <davidshe...@googlemail.com> wrote: > hi, > > after i setup lm_sensors on my gentoo amd64, i ran sensors, and got > the below output > > coretemp-isa-0000 > Adapter: ISA adapter > Core 0: +61.0 C (high = +74.0 C, crit = +100.0 C) > > coretemp-isa-0001 > Adapter: ISA adapter > Core 1: +61.0 C (high = +74.0 C, crit = +100.0 C) > > atk0110-acpi-0 > Adapter: ACPI interface > Vcore Voltage: +1.14 V (min = +1.45 V, max = +1.75 V) > +3.3 Voltage: +3.23 V (min = +3.00 V, max = +3.60 V) > +5.0 Voltage: +4.84 V (min = +4.50 V, max = +5.50 V) > +12.0 Voltage: +11.90 V (min = +11.20 V, max = +13.20 V) > CPU FAN Speed: 2556 RPM (min = 0 RPM) > CHASSIS FAN Speed: 0 RPM (min = 0 RPM) > POWER FAN Speed: 0 RPM (min = 0 RPM) > CPU Temperature: +49.0 C (high = +90.0 C, crit = +125.0 C) > MB Temperature: +41.0 C (high = +30.0 C, crit = +90.0 C) > > > at the top are my CPU temp. of the 2 cores, usually they should be the > same. but at the bottom, there's another value, which is 49 in this > instance. which one is the correct value? why they are different?
AFAIK, neither is wrong or correct, they are usually measuring different things. coretemp is typically a relative temperature based on some scale like 0-100, using the digital thermal sensor in the CPU. It's not necessarily actual temperature measurement but it's an approximation that should be near a real temperature on most CPU models. In the past the approximation formula has changed between kernel versions and suddenly people see a 15 degrees change in coretemp, but all that really changed is how it is calculated. So keep that in mind if you notice a large change in coretemp someday in the future after installing a new kernel but the motherboard CPU temp doesn't change. The CPU temperature in the bottom section is from your motherboard's sensors, which could be temperature very near the CPU if not inside the CPU itself like coretemp. Both values independently are useful for seeing any sudden change, but there's no real value in comparing them to each other. If you want actual temperature like a thermometer then the motherboard reading (lower number) is probably more accurate I would guess. Hope I didn't confuse you even more :)
