What do these voltages mean?

Discussion in 'CPU, Motherboards and Memory' started by meniscus, Sep 18, 2006.

  1. meniscus

    meniscus Geek Trainee

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    Im running a program called lm-sensors on my computer. It monitors the current state of my hardware. Here is an example of the output it gives.......




    Adapter: ISA adapter
    VCore 1: +1.30 V (min = +1.42 V, max = +1.57 V) ALARM
    VCore 2: +1.49 V (min = +2.40 V, max = +2.61 V) ALARM
    +3.3V: +6.46 V (min = +3.14 V, max = +3.46 V) ALARM
    +5V: +4.92 V (min = +4.76 V, max = +5.24 V)
    +12V: +12.03 V (min = +11.39 V, max = +12.61 V)
    -12V: -19.87 V (min = -12.63 V, max = -11.41 V) ALARM
    -5V: -2.56 V (min = -5.26 V, max = -4.77 V) ALARM
    Stdby: +5.00 V (min = +4.76 V, max = +5.24 V)
    VBat: +3.18 V
    fan1: 2909 RPM (min = 0 RPM, div = 16)
    fan2: 0 RPM (min = 332 RPM, div = 16)
    fan3: 3308 RPM (min = 664 RPM, div = 8)
    M/B Temp: +41°C (low = +15°C, high = +40°C) sensor = thermistor
    CPU Temp: +46°C (low = +15°C, high = +45°C) sensor = diode
    Temp3: +41°C (low = +15°C, high = +45°C) sensor = thermistor






    I just want to know which of the following values/rails apply directly to the CPU itself.
    VCore1=1.3
    VCore2=1.49
    3.3
    5
    12
    -12
    -5
    stdby =5
    Vbat 3.18

    And Why is there 2 Vcore's. Is one of them the chipset?

    Thanks
    meniscus
     
  2. Big B

    Big B HWF Godfather

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    Assuming you're running a Pentium 4/AthlonXP system or newer, the CPU will be running off the +12V.

    I'm not sure why the dual vCores, but, it wouldn't surprise me if it was measuring the northbridge.
     
  3. meniscus

    meniscus Geek Trainee

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    I thought CPUs run off 3.3 and 1.8V supplies? Am i totally wrong to assume that? What are all the rest of those readings for?
     
  4. Big B

    Big B HWF Godfather

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    In the past, I believe they ran off the 5V rail, but CPU's began to require more juice, and they started switching them over to the 12V rail

    3.3V powers the RAM, PCI slots, AGP slots
    5V powers the drives, and older CPUs (P3 and older)
    12V powers CPUs (Pentium 4/AthlonXP and newer), SATA hard drives, PCI Express

    I'm not sure what the negative ones are for, but occasionally, some devices do require them, and if nothing else, they can be a ground wire, which are necessary.

    There are no 1.8V rails in any power supply I'm aware of, at least any current standards.
     
  5. meniscus

    meniscus Geek Trainee

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    Here is a sample of the readings taken from the bios just after running lm sensors. Why is it showing 2 different sets of temperture readings? They were taken just after 1 another!!

     
  6. Big B

    Big B HWF Godfather

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    That is odd. I'm unfamiliar with the program you're using, so I can't say anything about the quality of the software. You might snag Speedfan and see how that matches up just to get a second opinion.

    You may also want to find out if your motherboard's BIOS has a miscalibrated temp sensor. I don't know what motherboard you have, but if it's still using a thermistor in the CPU socket, it could be mis-calibrated.
     

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