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Thoughts on how to fix an insanely hot laptop (75C idle, 100+C load)


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It all depends on how the motherboard reports the temperatures. Basically what you have is called a thermistor. It's a small device that will heighten or lower the resistance depending on how hot/cold it is. You'd have to get a gold rated thermistor which means it's precise to +/- 1% of its rated value. Thermistors can go either way though. You can have thermistors lower OR strengthen its resistance value according to the temps. It's set up so you have a temperature, the thermistor adjusts its value, that electrical value is then measured by the motherboards fan controller. That fan controller THEN adjusts the fan speed according to the voltage output of that thermistor. If you have a 4 pin fan then that fan's reporting the temp's through the PWM wire, and then registering the fan speed through the yellow wire and adjusting accordingly

That's where it gets tricky because the fan controller might use increasing voltages from the thermistor to either heighten or lower the fan speed and vice versa. There is also ANOTHER setup where the fan speed is completely dictated by the fan itself (most commonly 4 pin fans but uncommon in most computers today).

It's really a giant confusing mess. What I would do is find a power supply that matches the fan's maximum safe voltage. Use the current(I) equation, I=V/R, to find out how big your resistor needs to be to limit the current going through the fan, then see if it spins up for half a crap. Quite literally the fan's board could be faulty and that's why it's not reporting to the motherboard or adjusting the fan's speed.

Another thing you might want to take into account is that I actually have a fan here that reports that it's spinning at 4k RPMS, but it's actually spinning 1/2 to 1/3 of that. Hope that offers a better explanation at what I'm getting at :P

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(You didn't lose me with that woooo)

The fan does work when the computer decides to do something (like when it sits at 99C for a minute). It will audibly spin up, and a noticeable stream of air will pour out of the laptop.

I have used HWiNFO and there isn't even a mention of a fan speed or controller (even on my previous laptop). I'm not sure if it is hidden by the BIOS or something.

So I would guess it is either some moronic thing Fujitsu has done or the controller is shot. (I'm leaning toward the former since I have seen over 10 Fujitsu T901s with this issue.)

So should I put a thermistor (with leads) and put it on the heatpipe or something? Or just use a standard resistor inline with the fan speed wire, and let the built-in controller do its thing?

Thanks,

atn

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I'd use just a standard resistor, I just thought of this but if you put a thermistor in-line with another one obviously it wouldn't work out very well lol. You'll have to find a standard resistor. But that in itself presents another problem, if the fan controller reads that the temperature is hotter because the current is going UP we will have the exact opposite effect. You would literally need to boost the voltage to the fan controller to have the desired effect lol. Like I said, its a crazy situation.

You'll have to take a multimeter to the fan leads and investigate. Basically, you'll have the computer at idle temps. Take a reading there and write down the voltage and the current. Next put a load on it to heat it up and take another measurement. If the fan speed goes up and the voltage from the PWM goes down then you're in the clear, if it's the opposite then a resistor won't do the trick.

Now there's two ways you will have to use the multimeter to get both current and voltage measurements. The first is the easiest which is measuring the voltage. All you have to do is put the positive lead on the PWM wire and the negative lead on the negative wire (black). Read the voltage, then heat it up and repeat.

To measure the current however you will have to basically insert the multimeter so that it is in series with the fan. You'll have to disconnect the PWM wire attatch that to the positive probe on the multimeter, then take the multimeter's negative probe and put it on the lead where the PWM connected to.

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UPDATE! (and partial success story).

I got some washers to put between the screw head and the heatsink (there are springs on the heatsink posts themselves so this pretty much just compressed the springs more).

I made a offset plate for the fan. Now the fan sits directly on the heatsink with no gap.

Sitting at ~45 idle. I ran the ThrottleStop benchmark on 4-threads 1024M. I went from a completion time of over 800 seconds to ~650 seconds. CPU did not throttle at all (according to RealTemp). No longer having 100C temps under load. It still gets into the 90s, but that is only under a full load.

I haven't tried the fan mod yet.

Yay modding!

atn

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UPDATE! (and partial success story).

I got some washers to put between the screw head and the heatsink (there are springs on the heatsink posts themselves so this pretty much just compressed the springs more).

I made a offset plate for the fan. Now the fan sits directly on the heatsink with no gap.

Sitting at ~45 idle. I ran the ThrottleStop benchmark on 4-threads 1024M. I went from a completion time of over 800 seconds to ~650 seconds. CPU did not throttle at all (according to RealTemp). No longer having 100C temps under load. It still gets into the 90s, but that is only under a full load.

I haven't tried the fan mod yet.

Yay modding!

atn

Yay. Drop temps another 10C and you can get a quad.

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Very nice, fan wouldn't be the issue if your temps went down that much with just it's position. Glad ya figured it out! :D I was sorta hoping it wouldn't be the fan just because doing that mod I was talking about would be a reaaaal pain lol

Really the last thing you could try is just taking the RPM pin out of the connector and seeing if the fan will default at 100%, that'll be about the maximum amount of cooling you'd be able to get without actually modding the case or anything like that.

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I measured the voltages on the fan while at idle and while spinning (computer at load)

When the computer is idle with the fan off:

PWM: 3.225V

Pos: 0V

When the fan has a load and the fan is spinning:

PWM: 1.616V

Pos: 3.541V

By this I would guess the resister inline with the PWM wire would be a bust.

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Yeah, obviously the voltage on the positive wire would go up since the fan is spinning faster, however the PWM is going up as well so that means a resistor would only lower that, causing the fan to spin less. Let's say if the PWM read the opposite we could put a resistor on it and lower the PWM, in essence, increasing the fan speed. Unfortunately that's not the case. But hey, at least your temps are somewhat controllable now which is more than ya started with :D

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Yeah, obviously the voltage on the positive wire would go up since the fan is spinning faster, however the PWM is going up as well so that means a resistor would only lower that, causing the fan to spin less. Let's say if the PWM read the opposite we could put a resistor on it and lower the PWM, in essence, increasing the fan speed. Unfortunately that's not the case. But hey, at least your temps are somewhat controllable now which is more than ya started with :D

The PWM goes DOWN when the fan speed goes UP. The issue arises when the computer would want to turn the fan OFF, there would be a non-fan-speed-at-zero PWM voltage so it would be stuck trying to decrease the fan voltage to a sub-zero number. Unless this is fine, then a resistor in-line might work.

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The PWM goes DOWN when the fan speed goes UP. The issue arises when the computer would want to turn the fan OFF, there would be a non-fan-speed-at-zero PWM voltage so it would be stuck trying to decrease the fan voltage to a sub-zero number. Unless this is fine, then a resistor in-line might work.

You don't seem to understand what PWM is. Pulse width modulation. A fixed frequency and fixed voltage are applied. In this case 25Khz at 3.3V. The voltage never varies from 3.3V, but the multimeter will read lower voltages depending on the duty cycle of the PWM signal. For example if the duty cycle is 50%, the voltage of the PWM line will be 3.3V half the time, and 0V half the time, for an average of 1.65V. If the duty cycle is 75%, then the voltage is 3.3V 75% of the time, and 0V 25% of the time, for an average of 2.475V.

PWM is weird so an inline resistor might work. For a water cooling pump I have it takes a lower duty cycle % to run full speed at 3.3V than 5V.

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I know how PWM works, and since it is kinda screwy in some cases I was hoping a resister in line might work. (Similar to dimming an LED, you can have a lower frequency PWM or lower the voltage a little bit.

I'll give it a whirl tonight with a low ohm resister I can find lying around.

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I love the posts from the people helping. I myself found your little link to the laptop cooling mod very insightful. I can look no further then this thread with my problem. Thanks.

What kind of laptop do you have? I'll have some more pictures of the innards of mine after I get it working a little bit better. Hope it will help someone.

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What kind of laptop do you have? I'll have some more pictures of the innards of mine after I get it working a little bit better. Hope it will help someone.

I got my new Y500 with the dual GT750m last week. CPU temp (i7 3630QM) went really high when gaming, for example when playing Source game Dota 2 it was hovering at 90C. I did thermal repaste and tried to screw on the heatsink as tight as I could, and the temp dropped by about 5C on average.

Still the idle temp is kinda high at about 60C. On the other hand, the GPU that shares the same heatsink with the CPU only idles at 47C.

I am trying to do the BIOS mod, and hopefully there might be some way to undervolt it. Right now I am using ThrottleStop because when CPU and GPU are both under load, the CPU won't higher than 2.4GHz. Using TS, I can make it run at 3.2GHz.

- - - Updated - - -

Also, do you think that swapping the 45W 3630QM with a 35W 3632QM would help?

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I got my new Y500 with the dual GT750m last week. CPU temp (i7 3630QM) went really high when gaming, for example when playing Source game Dota 2 it was hovering at 90C. I did thermal repaste and tried to screw on the heatsink as tight as I could, and the temp dropped by about 5C on average.

Still the idle temp is kinda high at about 60C. On the other hand, the GPU that shares the same heatsink with the CPU only idles at 47C.

I am trying to do the BIOS mod, and hopefully there might be some way to undervolt it. Right now I am using ThrottleStop because when CPU and GPU are both under load, the CPU won't higher than 2.4GHz. Using TS, I can make it run at 3.2GHz.

- - - Updated - - -

Also, do you think that swapping the 45W 3630QM with a 35W 3632QM would help?

Don't so happen to have the UltraBay fan thing? I would love to get it (I know you can't use it with the SLI video cards since that is in the slot).

I'm sure using the 3632QM would help with temps if you don't mind the slight performance hit. I idle at 60C when I'm at home with my full setup (45-55C is when I'm on the go with more battery optimized settings). So your 60C with a quad isn't too terrible (I have a dual). The difference in temperature is kinda odd though. What is the order of the components?

GPU -> CPU -> radiator?

CPU -> GPU -> radiator?

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The Y500 I have has an Ultrabay on the right. I took it apart yesterday. It's a full fledge GPU but the PCB's shape is weird, unlike the normal MXM format.

There's two heatpipes for each GPU and CPU. The CPU is actually closer to the radiator. The whole think is one big aluminum plate.

I don't mind getting the 3632QM, since there's only at most 10% decrease in performance. But I am not entirely sure if the 3632QM would run that much colder. Even at 3.2GHz, according to ThrottleStop the 3630QM is pulling only about 30W.

My stolen Acer also idles at about 60C, and it's a 3317U 17W CPU...I guess Ivybridge runs hot. As long as the computer doesn't crash I am fine with higher temp. It's just annoying that the main vent is on the left and sometimes my pinky finger goes over it when I am gaming. And it's HOT.

I'm going to flash the modded BIOS and see what settings are there. Finger crossed I don't brick it.

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The Y500 I have has an Ultrabay on the right. I took it apart yesterday. It's a full fledge GPU but the PCB's shape is weird, unlike the normal MXM format.

There's two heatpipes for each GPU and CPU. The CPU is actually closer to the radiator. The whole think is one big aluminum plate.

I don't mind getting the 3632QM, since there's only at most 10% decrease in performance. But I am not entirely sure if the 3632QM would run that much colder. Even at 3.2GHz, according to ThrottleStop the 3630QM is pulling only about 30W.

My stolen Acer also idles at about 60C, and it's a 3317U 17W CPU...I guess Ivybridge runs hot. As long as the computer doesn't crash I am fine with higher temp. It's just annoying that the main vent is on the left and sometimes my pinky finger goes over it when I am gaming. And it's HOT.

I'm going to flash the modded BIOS and see what settings are there. Finger crossed I don't brick it.

hi my friend let me help get you into something laptops have very weak cooling systems and yours is beast of a laptop i use laptops for 10 years and i always modded my laptops as i hate things slowing down because of the temps first lets come to your cpu its a beast man its almost as fast as a desktop 2600k at stock voltages so you need really better ideas to cool down that much power with all mods i did my laptops the best one was opening bottom case and blowing cool air with a 15dollars aluminum notebook cooler it dropped my temp 30C yes ım not lyıng ıt dıd that than i understand that only thing a laptop needs to be cool is just fresh air in it

thats the main idea which you should base your mods on it opening bottom case with a laptop is the ugliest thing you can do to a laptop anyway maybe you can breaks one of yours and request a new bottom case from lenovo so you can mod one that you have : ) drilling holes and using a steel mesh is your best bet for now if you want really desktop like temperatures and there is one more thing you can do i know lenovo laptops have big meshes on theyre bottom already so youre lucky that you dont have a asus g series notebook

just mod your laptop cooler

the thing you need is air pressure in your laptop you dont have to kill your brain trying to create new ideas as i already did that first get a good 12volt cooler fan those working more silent and have high cfm rate which cooler master akasa noctua like fans and you have to stick on your laptop bottom meshes but try to stick it tight as possible you can use some silicon on fans blowing side just dont let air escape make sure fan put all air in your laptop to get highest pressure

sorry i have really bad english i have no education for it at all i wish you could get the idea now do your own mod just for your laptops physical qualities its really a easy one you can mod a laptop cooler to work at higher rpm using a mre powerful adapter with it and mod the cooler to get most air pressure in your laptop

thing you need is just air circulation in your lappie youll get amazed by the results you get with that using a aluminum laptop cooler or just a alumınum pad with some holes drilled with your fan is makes it cool better

sorry for no punctuation at all : )

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I used to take off all the bottom covers and set the laptop on a box fan. It worked, but it isn't what you call portable.

I'm actually designing how to add a 2nd fan and some more heatsinks to cool this thing down. I should have some results up this weekend.

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Here are pics of my offset plate mod:

post-6146-14494995138227_thumb.jpg

After seeing this:

http://forum.techinferno.com/alienware-m17x/3479-m17x-cpu-fan-upgrade-mod-2cfm-10-4cfm.html

I hunted around for a similar style fan, and found one!

post-6146-14494995138581_thumb.jpg

Now to make it fit (since the housing type is completely different I modified my old shell)

post-6146-14494995138774_thumb.jpg

Used some index cards as spacers, glued it in, and it works great!

I also pulled the PWM pin out for full fan speed, and the temps were insane.....ly great!

post-6146-14494995138936_thumb.jpg

This a few moments after running a TS Bench 4 thread 1024M test.

After reattaching the PWM pin, it is just a smidge under it's previous temps, but more effective at the high end.

As for what I pulled the fan out of.... Let's just say I would love to cram it in my laptop. The CPU plate is on the wrong side, but the shape of the radiator is perfect, and the pipe shape is great. I just don't have experience doing this.

post-6146-14494995139102_thumb.jpg

More concern now though:::

Where my heatsink makes contact to the CPU and dGPU looks like ... really bad.

I attempted to take some pics with my phone (potato quality camera):

CPU side:

post-6146-14494995139342_thumb.jpg

dGPU side:

post-6146-14494995139509_thumb.jpg

In case it isn't too clear. The pads are pitted and pretty scratch up. Even looks like some burn marks...

What should I do?

post-6146-14494995138021_thumb.jpg

post-6146-14494995138413_thumb.jpg

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I can't make anything out of your pictures. It's common for thermal paste residue to be left behind. Many pastes will leave a haze that is difficult to remove.

If that radiator really is a perfect fit, then you can swap the radiators with a toaster oven, solder paste, and some C clamps. Your current radiator sucks, but that one is good. They will have used 63/37 solder, which melts at 183C/361F. Don't go much hotter or else the heat pipes will burst. If you are seriously considering the radiator swap, PM me.

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