Possible CPU issue?

Hi folks,

I've read great stuff here over the years and this is the first time I needed to post a specific question. Here we go:

My core 2 duo E8400 Wolfdale 3.0GHz processor has been in my system since January. I had a pretty good cooler, but in the last week I noticed that I kept getting CPU Temp warnings from the ASUS monitor. (board is ASUS P5N-D).

Admittedly lazy, I bought a new cooler a few weeks ago and the problem went away (so I never bothered to change the cooler). Today the system was shutting itself off; hard stop, no warning no blue screen just power-out. CPU temp was hovering just under 59C.

I installed the new cooler (very nice, very well rated) and the problem seemed fixed... for about 2 hours. Then I had the same issues. In fact, I had a no-boot situation; power on mboard, fans would operate but no boot, no way to get into BIOS config. I have one solid green light on the Asus board when power is applied; that stays steady and constant regardless of what's going on.

I reset CMOS, no help. Reseated all cards, no help. Reseated memory, no help. Reseated the CPU and got a boot! Immediately went into BIOS config to monitor CPU temp (as suggested on this board). CPU temp was 54C for approximately 7 minutes, then the system shut itself off again - very abrupt, as if I had simply pulled the AC cord out of the wall.

I'm a pretty vanilla user; no overclock, no extreme gaming. As mentioned previously I had gotten several alarms for CPU temp in the last month (60C was the threshold in ASUS).

Have I fried this CPU?

PS - The original cooler was a freezer pro 7; fan was working, as were the 2 case fans and the PS fan. It was originally installed in January with arctic silver paste.

Thanks folks!
10 answers Last reply
More about possible issue
  1. Hello, and welcome to THG.

    Have you tested your PSU? Also, have you tested other components individually?

    Start with one stick of RAM and test each one of them. After you have tested each of them, go to other cards and remove to test them.
  2. I also would suspect a power issue. Could you post back with a complete list of parts for you PC? Also, are you certain you've seated the CPU correctly and used the proper amount of TIM?
  3. 54c is pretty high for sitting in the bios. I suspect the HSF isn't on correctly.

    As for your problem I think its power related. What PSU do you have?
  4. Thanks everyone!

    First off, I agree 54 is too high... but remember that I was experiencing NO SUCH ISSUE January-April with the FreezerPro cooler; the temp issue came up a few weeks ago and I then switched the cooler to an even larger unit. I'm thinking that HSF seating is not a problem based on these facts. (Meaning, I had seated the FreezerPro back in January and it ran Jan-April with no problems whatsoever).

    I just pulled ALL the memory out of the system and gave it a quick try - no boot, though I did get fans and power lights, etc.

    The power supply is a Corsair TX650W, also a January install. I re-seated everything (both MB connections, drives, fans) but no joy there either.

    What else? I believe I have used the correct amount of thermal paste, and I will post the complete parts list as soon as I get back to the system (need to head out for a few hours... because after the last 2 days I'd hate to throw the whole thing through the window).

    I have a power supply tester on order from NewEgg and should be able to get to it next Friday.

    Once again thanks very much!
  5. Update - started to rain so I didn't go out. Labeled each stick of memory and put #1 into the first slot. Got a good boot, system ran for 10 minutes under BIOS utility.

    Spoiler alert: I think my Vcore voltage is low.

    Cpu 53 constant from moment of boot, 54 at 5 min in. 55 at 7 minutes.
    Mb 31 rising to 33 then 36

    Vcore 1.21
    3.3 3.28
    5v 5.08
    12 12.03

    These values did not change for 10 minutes.

    Then went into Windows and noticed some differences, specifically in Vcore readings. 1.09 was the most constant reading, though it did occasionally fluctuate up to 1.23. The 5v reading was reasonably constant at 5.08, though I did notice occasional readings of 5.11.

    NOTE - There are differences between what SpeedFan reports and what the Asus utility reports. I'd like to say that this seems to be a 'lag' between them (when one is unchanging the other matches it, but when one changes there seems to be a discrepency). the differences seem to be in the range of .01 to .02.


    I had 4 sticks of G-Skill DDRII PC2-6400 memory, 2GB each for a total of 8. Currently running just one stick.

    I have 2 NVIDIA GeForce 9500 GTs. Just ran SpeedFan and GPU 1 is at 50C, GPU2 is at 46.

    The new CPU fan is the Zalman CNPS9900NT; overall dimensions are 94mm by 131mm by 152 mm. This thing is 'freakin huge', to use the technical term. The fan has been running at 2000 RPM.

    Case fans. This is an Antec case (a few years old). PS is at the bottom rear with drives at the bottom front; the drives have a small 2-fan cooler on them and run at around 38C.

    The CPU is located 'top and rear' and has 2 fan bays directly above and directly behind. I have the CPU fan blowing up, with the top case fan blowing out (airflow same direction). The rear fan is blowing IN; I had originally had it exhausting as well (thinking that at the top of the case I should be exhausting only) but changed it around this weekend.

    I could put another fan at the bottom of the case, in between the front bottom (drives) and the rear bottom (the PSU). The bottom of the case is fairly isolated by an aluminum wall; I would describe it as a 'tunnel' that links the drive bay with the PSU.
  6. Oh - the system ran for 30 minutes and I shut it down myself. I did notice that there's an unused drive bay middle-front of the case; if I remove that bay (it slides out) I can put in one more fan.
  7. If its starting that high there is something wrong. Most likely the HSF isn't on correctly and needs to be checked.
  8. I'm not sure I agree - simply because I had a cooler on there for months with NO issues and then started getting heat warnings. I've reseated the new cooler several times; while it could be done incorrectly there's not THAT many ways to screw it up (that I can determine). If I had missed the thermal paste or misapplied it, sure.. but there's an appropriate amount of paste, the heatsink is centered on the CPU, the fan is running - not sure what else to do on the cpu fan, honestly.

    I'm more curious about the core voltage and the fact that the system will run with 1 stick of memory but not 4.
  9. Quote:
    If I had missed the thermal paste or misapplied it, sure.. but there's an appropriate amount of paste, the heatsink is centered on the CPU, the fan is running

    And the pins/screws are tight? When you first turn a computer on and look at the temps in the bios, it should be just a degree or two higher then ambient temps. So unless its 50c in your room, there is a temp issue. (or a sensor issue, I'm going by what I'm told here.)
  10. They are! Forgive me, but while I have only built a handful of systems (like maybe 6) in my whole life I really do understand how important it is to seat the CPU fan properly!

    What's bugging me a lot is that the system was stable with good cooling for months without a problem - and then the CPU started to overheat. Granted I took the lazy way out and just replaced the CPU cooler (which didn't work, obviously) but I think the problem lies elsewhere.

    I suppose at this point it's the MB, PS or possibly the CPU? I've never had good luck with these types of situations; the only PS I ever had go bad on me had the good taste to just die all at once (a pretty easy troubleshoot).

    Anyway, folks, I've dumped everything I can think of into this thread. If anyone has any thoughts I'd greatly appreciate it; I hope to be testing the PS in the next few days but can't really think of a way to test CPU or MB. (Incidentally, I did a visual inspection for bad capacitors but found nothing on the MB).
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