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Low Laptop CPU Temps after thermal paste change

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April 7, 2014 1:04:09 PM

Hello,

Today I messed around with my laptop (HP Pavilion DV9000). It got really high temperatures past summer (90ºC during load, and 60ºC idle), so I decided to open it and clean it up.

I cleaned everything, ended up replacing the CPU's and the GPU's thermal paste, since it had dried up (it almost looked like tin foil), and re-assembled everything. This is a 9 year old laptop, and it was the first time it was ever cleaned.

I booted it up, it was working, but something was odd. My CPU temperature was oddly low: it was 30ºC below the GPU's. I was getting a reading of 40ºC on my GPU, but a whopping 10ºC on my CPU. My ambient temperature at the moment IS around 10-15ºC (sorry, no thermometer for accurate measurement). I measured using Speccy on Windows XP, found the temperatures weird, booted up BackTrack 5 and using coretemp it was at 10-15ºC as well.

I put it under IBT for approximately 30 seconds which were enough for it to climb to 50ºC. I was afraid to leave it for longer since if I DID mess something up, and since I have no comparison from previous IBT (if it reached 90ºC during light gaming, no way I was going to run IBT!), I could end up burning it since throttling wouldn't kick in.

So, did I mess it up? Is there anything I can do to "fix" it? What do you guys recommend I do? Do 50ºC sound accurate? If it's giving incorrect low temperatures, it doesn't matter much, but does that 50ºC sound too low? Am I asking too many questions?

Thanks,
Kelthar
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April 7, 2014 1:17:57 PM

If that's accurate, that's great!

When it comes to temperatures, there is generally no such thing as too low. You don't have to worry about that. To see if it's accurate, I would take off the case and just touch the back of the CPU chip during load. If it feels about 50c, you're good. If you getting 90c, it will likely be just about too hot to touch.
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April 7, 2014 1:21:26 PM

the back of the cpu chip during load?
like under where the heatsink is?
Really OP, don't finger test cpu temps:p 
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April 7, 2014 1:24:19 PM

How else would you suggest he gauge whether his thermometers are working? If it is says 50 but it feels almost as hot as boiling water, then he'll know something is wrong. But if it's just warm, then 50's probably an accurate reading.
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April 7, 2014 1:35:22 PM

Reason I'm worried about it being too low is that my desktop, in the same room, water-cooled, doesn't get lower than 15ºC on any cores, yet the laptop does.

I can't touch the CPU itself, nor its back, but I can touch what I believe is the southbridge. To be able to touch the CPU I'd need to do some really weird tinkering, since the CPU is located in a place that is inaccessible unless everything is completely disassembled, and there are some circuits that go, partially, through the "case" itself.

I wonder if there are any temperature benchmarks of laptops from 2004/2005? Basically, if I get the same load temps, I can assume nothing is wrong (for high temperatures at least!). I searched a little but couldn't find anything, but I'm also kinda clueless regarding what to search for.
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April 7, 2014 1:43:41 PM

A cpu will always be above room temperature, even on idle. even when watercooled-that is a fact-unless you cool it with icewater or something that itsself is below room temp.
If you say that your coretemp is equal to room temperature, then there most probably is a sensor error.
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April 7, 2014 1:45:48 PM

Eggz said:
How else would you suggest he gauge whether his thermometers are working? If it is says 50 but it feels almost as hot as boiling water, then he'll know something is wrong. But if it's just warm, then 50's probably an accurate reading.


Just as a point, you can't touch the back of the CPU, because a heatsink is on it.
If you remove the heatsink, temps will skyrocket and you risk burning out your cpu whatever the defect may be.
So no, putting your finger on the cpu to see how hot it is then compare it to the temps on your sensors is just a silly idea.
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April 7, 2014 2:00:55 PM

How would you even think it's possible to touch the top of a CPU while the CPU's cooler is on it? If you read the post carefully, you'd have noticed that I said in my post to touch the back of the CPU, which is possible. There are two sides to the main board. Just have the computer apart at the time. It's pretty simple. I've done it on laptops, even though it's a tight squeeze. It's really easy to do on a desktop, especially if you have a case that lets you remove the case walls from both sides.

If you just don't want to take things apart enough to be able to touch the back of the CPU, that's another issue. But there's no problem with touching it once it's taken apart.
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April 7, 2014 2:02:18 PM

I'll therefore assume the CPU is only faulty for low temperatures. The link that sunder25 posted shows 47ºC under load, which seems around the same I get (I got 50ºC after 30 seconds IBT), and according to one of the replies there it seems like a "correct" temperature.

That being said, I'll open it one last time to fix a small circuit which I probably forgot to plug back in (touch panel for media control), will format, install Windows 8.1 and report back.
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April 7, 2014 2:11:24 PM

Eggz said:
How would you even think it's possible to touch the top of a CPU while the CPU's cooler is on it? If you read the post carefully, you'd have noticed that I said in my post to touch the back of the CPU, which is possible. There are two sides to the main board. Just have the computer apart at the time. It's pretty simple. I've done it on laptops, even though it's a tight squeeze. It's really easy to do on a desktop, especially if you have a case that lets you remove the case walls from both sides.

If you just don't want to take things apart enough to be able to touch the back of the CPU, that's another issue. But there's no problem with touching it once it's taken apart.


I see, you mean back of the motherboard. I considered that, but that seems just as silly.
This seems like a pointless argument, when it comes to electronics, touch it and see how hot it is, and calibrate your sensors just is blunt and inaccurate.
I've attatched a picture of the back of a laptop motherboard. The x there doesn't express "touch me to see how hot i am in case the cpu sensors are not working properly" -if i was abrasive i am sorry, i didn't mean to be.

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April 7, 2014 2:21:33 PM

sunder25 said:
I see, you mean back of the motherboard. I considered that, but that seems just as silly.
This seems like a pointless argument, when it comes to electronics, touch it and see how hot it is, and calibrate your sensors just is blunt and inaccurate.
I've attatched a picture of the back of a laptop motherboard. The x there doesn't express "touch me to see how hot i am in case the cpu sensors are not working properly" -if i was abrasive i am sorry, i didn't mean to be.



I guess. It's just an easy, safe, and effective way to perform a quick reality check, especially when a computer's already taken apart.
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