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CPU speed slower than usual, laptop shuts down and won't turn on

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  • Laptops
  • CPUs
  • Shutdown
Last response: in CPUs
June 12, 2013 7:18:22 AM

My laptop's CPU is Intel i7-720QM 1.6Ghz.
3 weeks ago, the laptop got really slow that I had to do a reboot. But it randomly shut off after 5-60 seconds after boot (sometimes during Windows loading screen, sometimes after I logon to the computer, sometimes when I was in BIOS). I guessed it was because of the overheating (my laptop overheats a lot), so I cleaned out the fan's dust, reapplied thermal paste on CPU and GPU.

After that the laptop was back to normal, running 20 degrees cooler. But the problem happened again yesterday. It got really slow, now I noticed the max CPU speed was only 0.91 Ghz (not 1.6 Ghz as usual). I rebooted, it turned itself off around 5-60 seconds after boot like before. I did several tests and knew that it's not hard drive, RAM, or power cord issues. I had no idea why the CPU couldn't get to full speed and created the problem. My current guesses are:
- Battery and power cord are fine. Maybe the power connector inside the laptop is faulty?
- CPU
- Fan: fan is still running. But is a slow fan affect the CPU speed?
- Heatsink
- Faulty motherboard

I'm trying to figure out the faulty part to get a replacement. Any help would be appreciated. Thanks!

More about : cpu speed slower usual laptop shuts turn

a b à CPUs
June 12, 2013 7:25:04 AM

When a laptop powers off it is almost certainly overheating. You said you cleaned out the fans but have you cleaned out all the vents? Laptops have several vents to aid in dissipating heat.

I have never run across a situation where a faulty motherboard would allow you to boot the PC (except busted capacitors).

Try and blow out the vents with compressed air. If you think it is a faulty fan then attempt to purchase a new one but know that if you have it installed professionally then it will cost you.
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June 12, 2013 7:40:14 AM

sdogg1m said:
When a laptop powers off it is almost certainly overheating. You said you cleaned out the fans but have you cleaned out all the vents? Laptops have several vents to aid in dissipating heat.

I have never run across a situation where a faulty motherboard would allow you to boot the PC (except busted capacitors).

Try and blow out the vents with compressed air. If you think it is a faulty fan then attempt to purchase a new one but know that if you have it installed professionally then it will cost you.


Thanks. I did clean out all the vents. The CPU and GPU temperature while it ran very slow is only 45-55C so I don't think they're overheating. Maybe the fan is overheating?? (I'm no expert about this)
I'm a college student so buying fan, heatsink, motherboard all together to see which one is faulty is a bit expensive for me. That's why I'm trying to figure out the faulty part :p 
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a b à CPUs
June 12, 2013 7:54:20 AM

What is the manufacturer and model of your laptop if you don't mind me asking?
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June 12, 2013 7:58:06 AM

It's a Dell Studio 1558. I've had it for 3 years. It used to overheat a lot 60C idle - 95C max. After I cleaned the fan and vents the temperature dropped to 45C idle - 80C max
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June 12, 2013 8:06:53 AM

Perhaps you need to reseat the heatsink. If the pressure isn't just right and even all around, you may have a poor transfer of heat, but your #s for a laptop seem pretty good.

You may also want to check around as much as the PCB as you can see to locate any potentially bad capacitors.

Reset the BIOS? Any updates for that machine's BIOS?
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June 12, 2013 8:26:51 AM

You need a cooler pad, it connects to a usb port and sits under the laptop. Make sure you don't sit the laptop whether you use a cooler pad or not, on clothing, bedclothing, sheeting any sort of material other than wood, and definitely not your lap.

Take note of the underside of the laptop, there might be a fan exhaust that can get convered by extraneous things like loose sheets of paper, your knee, and the laptop case.
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June 12, 2013 9:21:58 AM

I have the latest version for the BIOS. I already reset the BIOS but the problem still persists. There was a time the laptop turned off while I'm in the BIOS. I'll take a look at the PCB capacitors tonight and see if anything is broken
I have a cooler pad. I'm strict about where I put my laptop so I make sure nothing is blocking the air in and out.
Thanks guys.
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June 13, 2013 12:18:55 AM

So, the cpu is slower ..... what ever did you do that caused it? New game? Program? Diagnostic utility?

What free space? Did you partition the hdd at any time? Did you re-install the OS or is it the original?
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June 13, 2013 6:09:17 AM

You could always try an OS refresh, make sure you don't have any malware that would restrict the CPU speed in any way, etc. Unlikely but possible.
I have a rather large 12 cell battery for my laptop which hangs out like a fat ass. You could try getting one of those (they don't cost that much) to see if the elevation helps the airflow.
Some programs within Windows (like, for example HP Coolsense) downclock the CPU when it gets a little bit too hot just so it can cool down more quickly. Make sure there aren't any of those lying around where they aren't welcome.
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