Tj Max 100C - Cause for Alarm?


I hope I've posted this in the right section! :)

I've been having this recurring problem - but should I be alarmed?

At least 5 or 6 times a week, my desktop suddenly becomes non-responsive. That is, none of my programmes/applications work or espond at all - though slightly curiously, I can still surf the web. I then have to turn my computer off - as it just freezes if I try to reboot. After that it works fine again - until the next time it becomes non-responsive. And so on.

I am 99-100% certain it is nothing to do with viruses, spyware, adware, malware, etc - as I've ran near endless scans & checks (including online ones) and nothing of any importance is ever found. And when I go to Administrative Tools/Event Viewer, no warnings or alerts are flagged up. In which case, it strikes me as fairly logical to think that it might be something to do with Temperatures and/or Voltages.

Yes, all my fans seem to be whizzing around how they should.

So, I installed Core Temp 0.99.1. On average - and as I write, with the PC having been on for a couple of hours - Core #0 is 30C and Core #1 is 31C - which seems OK to me. However, my "Tjunction" temperature is around 100C - which, to my (albeit non-expert) ears, does sound rather on the high side. Maybe alarmingly so.

Next, I installed SpeedFan 4.34 - and, yes, there is indeed a warning about the Core temperature being 55C. I then enabled Automatic Fan Speed - but nothing seemed to change. And I am uncertain as to how to properly use or configure SpeedFan. I have sent an email to the author of SpeedFan outlining my problem (or potential problem).

Finally, I installed RealTemp 2.70 and it told me this:

Core Temperature - 26C, 27C

Distance to TJmax - 69C, 68C

Minimum temperature - 26C, 26C

Maximum Temperature - 28C, 34C

My Tech Specs are: XP Home+Vista Ultimate (32-bit) \ Intel E6750 @ 3.47 \ Abit IP-35 Pro \ Antec 900 Ultimate Gamer \ Arctic Cooling Freezer 7 Pro \ 2gb Corsair Twin2X2048 XMS Xtreme Performance (800mhz) \ XFX 8800GTS 320mb \ Samsung SpinPoint T 500gb \ Plextor PX-740A \ Corsair CMPSUHX 620w PSU \ Speedtouch 510 v6.

By the way, all this is happening on XP Home (my 'default' O/S) and I am currently NOT running it Overclocked with the Abit uGuru software - that is, everything is at 'defaults' (including my Graphics Card).

Have you got any tips or advise on what I should do next? If you have, that would be much appreciated!

Anyway, I look forward to hearing from you,

6 answers Last reply
More about 100c alarm
  1. TJMax is the temperature value at which your CPU cores will begin throttling in order to prevent overheating. You can also think of it as the maximum temperature your CPU will run before it tries to save itself. The cores can actually run hotter before dying, but if you have thermal throttling enabled, then TJMax is as high as it can go before lowering the speed. 100°C is actually not accurate, it should be 85°C for that processor (or whatever Real Temp says, maybe 95°C). I would trust Real Temp, but not the other programs you listed. Real Temp is built based off of real-world testing where Core Temp and Speed Fan are based on guesswork.

    As for your problem... have you tried a repair install of the OS? Also consider that the hard drive could be going bad or that you may have a faulty power supply. Finally, test your memory with Memtest86+
  2. yuck. where to begin...well Tjuntion is always 100c. It is on every computer i've seen... i dont remember why...maybe cause it cant get a proper reading so it goes to 100? either way its nothing to worry about and not your problem.

    I'd like to think it has to do with how you're dual booting/ partitioning the drive. Did you try using any diagnostic tools to rule out hardware?

    Memtest86+ for your memory
    prime95 for cpu (even though its not oc'ed just run it to see if you get any error)
    do a disk cleanup/defrag/chkdsk for the HDD and then run HDtune and do an error scan.

    I like SIW, system information for windows, better than SpeedFan (more accurate) and its free. Oh and how hot is your GPU? might wanna check that temp. but yeah not sure bout the whole dual boot thing cause ive never gone through this process before. when did it start happeneing? might want to try a system restore if it wasnt too long ago.
  3. First off... there is no tjmax that the software can detect. Intel does not publish what the tjmax is. Any program (coretemp/realtemp/speedfan/hd monitor) that reads core temps rely on a tjmax. If you ever used those programs, you should notice different temps it reports. That is because the tjmax is a guess, an assumption of what it is.

    Also, you really shouldn't rely on core temps for idle temps. One reason why the tjmax does exist, is that it is part of a process for thermal throttling and thermal shutdown.

    It's perhaps best to go by the Tcase sensor, that your MB app will read, what your bios health monitor reads, and speed fan should also see that sensor. Intel does publish the thermal spec, which would be the Tcase max that you shouldn't exceed.
  4. Grimmy,
    Don't lump Real Temp in there. UncleWebb used actual real world measurements to determine TJMax. It varies, either 85 or 95 on the Core products. I believe it has to do with the process size (45nm vs 65nm). The way he determined this was:

    Core Temp = TJMax - DTS


    TJMax = Core Temp + DTS

    He found the Core Temperature at a given time by measuring with an infrared thermometer, accurate to within 1°C. So the formula became:

    TJMax = Measured Temp + DTS

    DTS (Digital Thermal Sensor) is reported by the core, so it's possible to calculate to within 1°C of the actual TJMax value.

    UncleWebb has tested numerous Core chips and a few other people have verified his results with the same testing method.

    Programs like Speed Fan and Core Temp have only guessed at the value. This guess is based on the TJMax value for Intel's mobile Core products which was publish as 105°C. Intel has not published the values for its desktop line processors, but testing has shown it is not as high as the mobile chips.
  5. What I'm trying to get across... It seems people assume that when they install and use a temp program, to read core temps, that it is correct. That the program actually gets a tjmax from the CPU. Which it does NOT.

    I never said anything about UncleWebb being wrong, but since you brought him up, in order to use ANY program that gives core readings, you need to calibrate it. (Even RealTemp)


    And if you ever used the "Test Sensor" on RealTemp, read what it says at the very bottom of the message when its done testing.
  6. Misunderstandings happen, so I just wanted to clarify.

    I didn't mean to make realtemp look bad, and needed it to clarify the different tjmax's of different programs that everyone would see a difference.

    But I'm glad we came to an agreement. :D
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