Testing CPU in exposed laptop w/o thermal compound?

hackyom

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Apr 10, 2014
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I have some Intel T7600 cpus I'd like to test using a Dell Inspiron E1505. Since I don't want to permanently install the cpus, I don't want to put any thermal compound on them and I'd like to leave the motherboard exposed to make things easier. I'll reinstall the heatsink between tests, but would prefer not to put the entire laptop back together.. maybe just "set" the top case on it.

Are there heat concerns by doing this? Could I place a large room fan over the laptop? Could I do something more extreme, like put the laptop in the refrigerator?

PS. By "test", I mean I'll run some kind of cpu diagnostics... most likely using the Intel Processor Diagnostics Tool via a Fedora Live USB.
 

Baralis

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Jun 10, 2010
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Thermal compound is a must particularly if you plan to stress or run tests the CPU. The small air spaces between the heatsink and CPU may seem trivial but air has a very poor heat transfer and will cause temperatures to reach critical in only a few seconds.

I know constantly reapplying compound is a pain but its necessary any time you remove a heatsink.
 

Eggz

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If you put the heatsink on, you'll be able to just see if the CPUs work by turning on the computer. I wouldn't put any kind of load on the computer, though. It'll heat up pretty quickly.

As for other solutions like the fridge, that won't work. Cooling works by making the heat concentration less dense, and then by blowing it away from the the heat spreaders. To illustrate the same thing, you can do an experiment. Take 2 shirts or rags of the same size, and soak them both in boiling water. Cool them both in different ways. The first will be balled up in the freezer, and the second will be hung up by the window on a hanger in front of a fan. The second shirt will cool much, much faster because the heat is less dense. That's despite the freezer being much colder.

The same goes for the CPU. Without spreading the heat, it's like the balled up shirt. Heatsinks make the CPU like the hung shirt. But that doesn't happen unless the heat transfers over to the heatsink to spread. Just putting the heatsink on without paste would be similar to putting a third shirt balled up near the window with a fan. It's a little better than nothing, but it really won't do much.
 

hackyom

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Apr 10, 2014
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Thanks for the responses... I was kind of afraid that might be case.


Soo.. in terms of a "quick - no thermal compound" test, would it be sufficient to just power on as far as the BIOS? ie, if one of the cpus is really "bad", I'm guessing it wouldn't even make it past the BIOS tests? And is that "safe"... or is even that too risky. I don't want to damage the cpus.

IF thermal compound is required to do any extensive diags (or perhaps just the quick power-on check), is there a specific type of compound that would be good for a temporary situation like this? ie, something that can easily be removed without risking damage to the cpu and/or heatsink?

Also... I do plan to permanently install ONE of the cpus, but I'd like to test them all. For a permanent install, is there a particular type/brand of thermal compound that will work best for this specific cpu (Intel T7600) in this specific laptop (Dell Inspiron E1505)?

And... is there any problems leaving the laptop open/exposed while I'm doing the tests? ie, will that reduce the ability for the fan/heatsink to work properly?

 

Eggz

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Bios would tell you whether the CPUs work. I mean, it's risky, but you could try to boot into Windows and start up the temperature program if the Bios passes. In the Bios, you'll be able to access the CPU temperature. If it's okay (i.e. below 75ish), then you will probably be okay for very low loads. I would save my least favorite processor for the first attempt at booting into Windows for the temperature software, though. It might not make it given the moderate load associated with booting up.

For paste, since it's so cheap, I would just get a good supply of the best stuff. Personally, I'd say to go with Arctic Silver 5 at only $8 - $10 per tube. Each tube will give you many applications. Buy a few tubes just to have it on hand. Also, Artcic Silver makes removal solvent so you can do it right.

Here is the paste for only $9: http://www.newegg.com/Product/Product.aspx?Item=N82E16835100007

Here is the removal solvent for only $6: http://www.newegg.com/Product/Product.aspx?Item=35-100-010%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20

With my single tube and removal solvents, I've replaced heatsinks on several CPUs and GPUs. It's really easy. Just take it off first with a paper towel or something that won't leave debris. Then (if you want to do it right), use the compound to make the surfaces super clean with a micro fiber cloth. Here is a pack of four for $21: http://www.bhphotovideo.com/c/product/520394-REG/Zeiss_1439_266_Microfiber_Cleaning_Cloths_Blue.html/prm/alsVwDtl

Also, just one for $5: http://www.bhphotovideo.com/c/product/374562-REG/Nikon_8072_Micro_Fiber_Lens_Cleaning_Cloth.html

It's also good to practice with the paste. Just do it a bunch, and you'll get good at doing it right for when you actually do your permanent replacement. It's easy, and I think you'll be able to swap the processor with paste in just a couple minutes after you get the paste, solvent, and cloths.

You'll be able to keep the laptop open during all of this. Just keep it on a non-conductive surface that won't cause static. Have fun! :-D