TechSpot

Diode temp is really high!

By efilflah
Sep 25, 2006
  1. Hey peeps I need some advice.

    The other day I bought Splinter Cell: Chaos theory (only a tenner) and I was excited to get going.

    After a short time playing it just froze. I rebooted my machine and checked the temps via the bios and my CPU temp as reported by the hardware monitor in the bios was 81C. This is the first time a game has locked up on me in years, but I've noticed the diode temp slowly creeping up gradually. A few months ago it was only 73C. My vcore is 1.725 in the bios (1.75 reported by probe), it's a bit high for a low OC but it's been stable like that for years so I didn't wanna touch it.

    According to ASUS Probe and Speedfan, my socket temp when idle is 43C - 46C depending on room temp, and under load (playing a graphics intensive game) it's about 51C - 55C again depending on the room temp. Just sitting here idle my diode is in the 70s which is definitely not right. Graphics card temp is fine. 40C idle and less than 60 coming off a hard gaming session, so I doubt its that.

    The diode is what matters though, and I can't figure out why it's so much higher than my socket. It should only be in the sixties really. I took off the HSF and reseated it but it didn't do anything. I've ordered some Arctic Silver 5 (lost my other one) and some cleaning fluid, so I'm gonna give it a good clean and then reseat it again, but if that doesn't work, I dunno what else to do.

    It seems unusually high, only 5C away from the maximum recommended temp, that can't be good :(

    Any suggestions would be appreciated, I'm no expert by any means.

    Thanks in advance.
     
  2. Tmagic650

    Tmagic650 TS Ambassador Posts: 21,067   +169

    You are talking about the thermal diode under the CPU on the motherboard? These diodes are notorious for being highly inaccurate in their heat sencing. They vary in accuracy from motherboard to motherboard. You have a long history of high temps. I would invest in a better HSF and let the temps go as they are...
     
  3. wolfram

    wolfram TechSpot Paladin Posts: 2,605   +9

    Or lower a little the Vcore voltage. 1.725 seems a little high for me. If you lower the voltage, surely it will run cooler.
     
  4. efilflah

    efilflah TS Rookie Topic Starter

    Thanks for the responses.

    Lowering the vcore will of course lower the temp, but my main concern is the fact that SC:CT locks up from time to time with my current clock. Even with a lowered vcore the diode temp is in the 70-80 range and the lock ups are still happening.

    After I eased back the overclock a bit it didn't crash once after a 2 hour session, so it must be the temps.

    Even if the reported temp is off by a few degrees it's still obviously running hot enough to cause instability which was never the case before when the temps were lower.

    The HSF has served me well all of these years, I dunno if it's worth replacing it, the system still has some juice in it and I'd rather hold out and do a major upgrade sometime in the future, but until then I guess giving it a clean and re-application of AS5 is the only option?
     
  5. Tmagic650

    Tmagic650 TS Ambassador Posts: 21,067   +169

    Ok efilflah,
    make sure that the fins on the CPU cooler are clean and free from dust. You might have to remove the fan to get to the dust though
     
  6. efilflah

    efilflah TS Rookie Topic Starter

    I did that when I reseated it. There was a bit of dust build up but it's totally clear now. The only thing I didn't do when reseating it was clean and reapply thermal paste cos I'd lost it (after moving house), so hopefully that'll solve it. I just gotto wait for the ebay delivery van......damn I hate waiting. :O
     
  7. efilflah

    efilflah TS Rookie Topic Starter

    So my AS5 and Cleaning kit arrived today and wow that old thermal paste was so lame.

    With my really low O/C to keep my system stable (185*11 vcore 1.725) before the cleaning and AS5 Application (note: today is quite cool).

    Before:

    Socket 43C Diode 72 Idle
    Socket 50C Diode 82 Idle


    After

    Socket 35C Diode 40C Idle

    I haven't tried it under load yet, but initial signs are :OMG: to me. I'll reset my clock back to what it was before (195*11 vcore 1.725) and see if I have any stability issues, but if the temps are reasonable, then there's no reason there should be and I may try pushing it further.

    I'm so happy right now.

    Thanks for the responses.
     
  8. Rik

    Rik Banned Posts: 4,985

    When i started to read all the posts i began to suspect thermal paste.
    Glad you got it sorted!!!
    But what do you mean by "diode" temp???? I worked in the electronics industry for over 15 years so i know what a diode is, but I've never seen diode temp referred to before.
     
  9. Tmagic650

    Tmagic650 TS Ambassador Posts: 21,067   +169

    Rik,
    there is a small thermal diode in the middle of the CPU socket on some motherboards. This diode transmits a "signal" to an IC that reports it to the bios. This temperature circuit works better in some boards than in others. This temp reading should only be used for reference and not as gospel though. Bad high temps= checking CPU HSF fit and thermal paste first
     
  10. efilflah

    efilflah TS Rookie Topic Starter

    Just played a bit of SC:CT at 195*11 and the diode only went as high as 45 socket went to 40 vcore 1.700.

    No crashes yet.....:):):)
     
  11. wolfram

    wolfram TechSpot Paladin Posts: 2,605   +9

    That's pretty good. Without a doubt, that AS5 is really helping to keep the CPU cool.
     
     
  12. Rik

    Rik Banned Posts: 4,985


    As i said before, I've worked in the electronics trade for 15 years. All the mobo sensors I've seen in the middle of the processor socket have all been thermistor based sensors as thermistors are very thermally unstable devices by design. As the temperature changes the resistance of the thermistor changes considerably. On the other hand, diodes are quite thermally stable as they are designed to only allow current in one direction rather than resist it. Germanium signal diodes are different tho as they are designed to create a signal but are also quite thermally stable. I cant see how a diode could be used as a temperature sensor!!!!!
     
  13. Tmagic650

    Tmagic650 TS Ambassador Posts: 21,067   +169

    Good point :) I know thermistors
     
  14. Rik

    Rik Banned Posts: 4,985

    So you see my reason for being confused!!! :)

    This is only a theory and i do not mean to offend anyone by this statement, but, i believe that the term "thermal diode" is a misconception made by those that know little or nothing about electronics. Am i right? Anyone have an opinion on my statement!!!!
    I will state once more that i mean no offence by that statement, I'm just trying to clarify matters.
     
  15. efilflah

    efilflah TS Rookie Topic Starter

    In truth rik, I have no idea. I just call it a diode because that's what everyone else calls it, I couldn't back up my claims that it's a diode even if I wanted to :D

    Either way, whatever it is, it's a lot cooler now and I'm happy 200*11 stable for the first time EVER!!

    *does happy dance*
     
  16. Tmagic650

    Tmagic650 TS Ambassador Posts: 21,067   +169

    Me too Rik,
    Photo diodes, tunnel diodes, zener diodes... I must have picked up "thermal' diode when I repaired circuit boards a long time ago. I've been retired since 2001 and I don't do much component-level now...

    No offence buddy! Thanks for the info ... and efilflah, congratulations on your cooler system :)
     
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