Takaharu

I recently upgraded my other PC from an E7300 to an E8400 but I've noticed a little bit of a glitch started occurring; when I turn the PC on the temperature of the CPU (apparently) starts climbing very rapidly, slowing down when it reaches the high end of the scale.
I haven't had a lot of experience with CPU fans with Core 2 Duo processors but I find it hard to believe that the CPU is running at 106 degrees Celsius (and climbing) after a few minutes of the PC booting up. I've also felt around the processor fan and touched the processor itself and, although warm, I don't think it reached anywhere near 100 degrees.

The CPU's not overclocked and I'm using a Core 2 Duo fan along with Arctic Silver thermal paste. The PC has an ASUS Commando motherboard with the latest BIOS. I've applied thermal paste a fair few times and I'd be surprised if it was that that causes the processor to exceed 100 degrees in under 5 minutes.

Could this actually be running that hot or is it more likely there's a fault with the motherboard's readings?

Tyrsonswood

It wouldn't hurt to re do the paste and re mount the HSF...... that would rule out something simple and easily fixed.

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Tipstaff

I would check 2 things:

1) Make sure that the heatsink is properly mounted. The toughest thing about the Socket 775 cooler is that the board tends to bend when you try to push the pins down, and sometimes the expandable pins won't be fully into the holes when you do push down the center pin. If it's not mounted completely, as soon as the heatsink heats up it will pop up slightly, and it won't be flush anymore, meaning it would overheat. What I tend to do is grab some paper, fold it up tight, and wedge it between the board and the case right above, or as near as possible to the CPU as you can. This keeps the board from flexing while you push down the pins.

2) Be careful of how much paste you use. It should just be a very thin layer in the center of the CPU. Since the paste will squeeze out when the cooler is mounted you don't want to cover the entire top of the CPU or it will squeeze out onto the socket/board itself. Which also brings up something else: double check the board and the socket to make sure you didn't get any dust or paste onto any of the pins or chips in or around the socket itself.

Edit: One more thing, and that would be to try resetting your bios, or at least loading the defaults. While your in there I would take a look at the bios settings for things like EIST (try having it on, as well as off), settings on how to deal with the fans (such as running them in performance, silent, or normal), and to see how the fan speeds are going (see if the speeds are fluctuating).

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Takaharu

Nope, already tried that. I re-seated the fan first of all, which didn't make any difference then I removed the fan, cleaned off all of the thermal paste (with proper thermal paste remover), re-applied the paste then re-seated the fan. For good measure I also reset the BIOS to default. That slowed down the temperature but it was still going up pretty fast. According to the readings in the hardware monitor the temperature started at about 55 degrees then raised quite quickly up past the 60 degrees mark.

Can a BIOS be down-graded to an older version? If so I might try that next.

Tyrsonswood

Most boards can be flashed up or down, just depends on what older versions are available.

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Tipstaff

The E8400 that you switched to, is it a new CPU, or did you buy it used off of someone? If it was used, do you know if that person was overclocking it? If it's new, you could try going back to the seller to get it replaced, or call Intel up for the same.

Right now the only 2 things that come to mind that could be the issue is that either motherboard is defective or not seeing the CPU correctly, or that the CPU is damaged.

BTW, if you do down grade the bios don't go any lower than bios 1801. If it's a newer E8400 (being revision E0) then you cannot go any lower than 1801. If it's an older E8400 (being revision C0), then you can go as low as bios 1605. If you don't know what revision of the E8400 you have then you need to keep a CPU handy that you can swap in that works on the bios you are intending to down grade to just in case the down grade doesn't work. That way you can easily upgrade to a bios version that you know works fine.

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Takaharu

It's a new processor. I'll try a downgrade this evening and if it doesn't work I'll try sending it back.

CDsDontBurn

this is what i was thinking.

if the CPU has already been mounted, re-mounted and re-pasted several times, it's going to be a faulty CPU, or it's going to be a motherboard issue. of course, provided that the BIOS has been resolved first.

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Takaharu

Here's what I did.

1 - I went out and got a replacement CPU fan. The one I was using was the stock cooler from the previous CPU, an E7300. That improved the temperature slightly but it was still pretty much as bad.
2 - I reset the BIOS, tried again but to no avail. I wasn't sure if the BIOS reset correctly because I haven't used the Clear CMOS feature before so I left it a bit longer. I was sure it did it the second time because some of the settings I had made were back to their defaults. Still no change in temperature, however.
3 - I re-seated the fan again. Better safe than sorry, right? Luckily the new fan came with its own supply of thermal paste so I could afford to re-apply the fan a few times. No real effect.
4 - I rolled back the BIOS to 1801 but the PC wouldn't boot. At all. It wouldn't even display the beginning of the motherboard logo. "Oh crap!". I hadn't sold the old processor yet so that went in next.
5 - The old processor worked fine (oddly enough) with the old BIOS. I booted into Windows and the temperatures were fine - under 45 degrees, even with Q-Fan. I decided to upgrade the BIOS back to the latest version and everything still worked fine. So, I thought it was worth trying the new processor again.
6 - After cleaning off the thermal paste yet again and re-applying it I re-fitted the new processor. I booted up and the temperature has been sitting around 45-50 degrees with Q-Fan enabled. I'm going to keep an eye on it over the next few days as thermal paste takes at least a couple of days to "set" properly.

So, looking good thus far. Not perfect but I'm quite content with 50 degrees idle, especially compared to >100 degrees.

Tyrsonswood

Good you got it working at "real" temps, seems like a mystery fix though because you don't know what the cause was..... (those things always bug me). Keep your eye on the temps, but you should be good to go now.

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