1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Official TjMax figures

Discussion in 'Overclocking & Cooling' started by HiltonSteve, Oct 30, 2008.

  1. HiltonSteve


    Joined: Oct 25, 2008

    Posts: 29

    Found these today, thought they may come in useful !

    If using Core Temp etc then you will need to adjust the TjMax value accordingly so that you get accurate figures.

    08:50 - Tuesday 21 October 2008 by Gavin Steacy
    Source: Tom's Hardware – Keywords: intel, dts, specs Category : CPU
    It has been a long time coming, but the pieces are slowly falling into place. Intel has now released the official Tjunction Max value for all 65nm and 45nm Core 2 processors at the Intel Developer Forum in Taipei.

    ZoomIn a previous report on the August IDF presentation in San Francisco, Tom’s Hardware discussed how the information provided by Intel had very little real-world value. The reason Tjunction Max (the temperature where thermal protection is engaged) is not the silver bullet for 45nm Core 2 processors is because the sensors suffer from extremely high amounts of "slope error," that is, they become less accurate as the real temperature moves further from Tjunction Max.

    An Intel document (PDF) describes the error on Atom processors, which use the same or similar DTS as those on 45nm Core 2 processors:

    "The digital thermal sensor (DTS) accuracy is in the order of -5°C +10°C around 90°C; it deteriorates to ±10°C at 50°C. The DTS temperature reading saturates at some temperature below 50°C. Any DTS reading below 50°C should be considered to indicate only a temperature below 50°C and not a specific temperature. External thermal sensor with “BJT” model is required to read thermal diode temperature."

    According to Intel, if the actual temperature is below 50°C the temperature can’t be trusted at all. With calibration, the slope error can be offset to an extent, but the reported temperatures will never be as accurate as those which are reported by the DTS on 65nm processors. Furthermore, the sensors can sometimes "stick," particularly at lower temperatures, and the worst of these sensors can’t be calibrated properly.

    Unlike their 45nm counterparts, the DTS for 65nm is much less affected by slope error, so that even a temperature readout that has not been calibrated can give a reasonably close representation of the actual temperature. The only major factor which will affect readings is Tjunction Max. Since the 65nm CPUs were released, enthusiasts and developers of temperature monitoring software have debated over the Tjunction Max. It was hoped that Intel would disclose these details at the August IDF; however, we were to be disappointed. A few months later and Intel has finally decided to disclose the Tjunction Max for every processor in the Core 2 line, both 45nm and 65nm, as well as Xeon server CPUs. The Tjunction Max values for all Core 2 processors are as follows:

    65nm Desktop CPUs Model Tj Max (B2/B3/L2) Tj Max (G0/M0)
    E6000 and E4000 series 70°C 80°C
    X6800 75°C 85°C
    Q6000 series 80°C 90°C
    QX6000 series 80°C 90°C
    QX68xx series 80°C 80°C
    E1000 series 75°C 85°C

    45nm Desktop CPUs Model Tj Max (Stepping unspecified)
    E8000 and E7000 series 100°C
    Q9000 and Q8000 series 100°C
    QX9650 95°C
    QX977x 85°C

    65nm Xeon Dual-Core CPUs Model Tj Max (Stepping unspecified)
    E7220, E7210 80°C
    7100 series 100°C

    65nm Xeon Dual-Core CPUs Model Tj Max (B2) Tj Max (G0)
    5080, 5060 80°C 90°C
    5063, 5050, 5030 80°C 90°C
    5160 N/A 80°C
    5150, 5140, 5130, 5120, 5110 N/A 80°C
    5148 N/A 80°C
    L5138 N/A 100°C
    3000 series 80°C 90°C

    65nm Xeon Quad-Core CPUs Model Tj Max (Stepping unspecified)
    X7350 90°C
    E7340, E7330, E7320, E7310 80°C
    L7345 80°C
    X5000 series 90/95°C
    E5000 series 80°C
    L5000 series 70°C
    L5318 95°C
    X3230, X3220, X3210 90°C
    XE 90°C
    XEE 80°C

    45nm Xeon Single-Core CPUs Model Tj Max (Stepping unspecified)
    L3104 95°C

    45nm Xeon Dual-Core CPUs Model Tj Max (Stepping unspecified)
    X52xx series 90°C
    E5240 90°C
    E5220, E5205 70/90°C
    L5240 70°C
    L5238, L5215 95°C
    E3120, E3113, E3110 95°C
    L3110 95°C

    45nm Xeon Quad-Core CPUs Model Tj Max (Stepping unspecified)
    E7440, E7430, E7420 90°C
    L7445 80°C
    X54xx series 85°C
    E54xx series 85°C
    L5408 95°C
    L5430, L5420, L5410 70°C
    X33xx 95°C
    L3360 90°C
    X33xx series 95°C
    L3360 90°C

    45nm Xeon Six-Core CPUs Model Tj Max (Stepping unspecified)
    X7460 85°C
    E7455 85°C
    L7455 85°C

    The above data will mean that for some users the temperatures currently being reported for their cores are actually quite a fair amount off; assuming we take Intel’s word for these maximum temperature values. For example, most temperature reporting programs would use 85°C as the Tjunction Max for a B2 E6600. According to Intel, the "official" Tjunction Max for this processor is only 70°C. That means that for a program which does not take into account any slope error, the temperature would be reported 15°C too high.

    Of further interest is that many enthusiasts have done extensive testing to approximate Tjunction Max where it had not been specified. For the 45nm processors, Intel’s data generally aligns with the results of community testing. However, for 65nm the values provided by Intel are significantly different for some processors than what testing has shown. It may very well be that Intel has caused even more confusion than before.

    You can expect most software developers to update their programs in the near future to reflect the information provided by Intel.

    Link - http://www.tomshardware.co.uk/intel-dts-specs,news-29460.html
    Last edited: Oct 30, 2008