Techniker

Honorable
Sep 20, 2013
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10,520
Hey all,

Time for the hourly post on core temperature concerns.

As stated in the title, I have a Dell E6430 ATG with an i7-3740qm processor onboard- I had to rebuild this laptop (the subchassis was cracked clear through) and as I was rebuilding it, I noticed that the thermal paste was dried out. Not having any thermal paste onhand, I started to monitor core temps after the rebuild. Typically the computer would idle at 54-56 degrees and under typical "business" semiloaded use would go to 58-60 degrees. However, running a Dell diagnostic test (with CPU stress test) in the BIOS, I did receive a thermal overtemp warning (hitting 99 degrees C before it presumably would downthrottle). The laptop has never had an emergency thermal shutdown event.

A few days later my Arctic Silver 5 and prep chemicals arrived and I applied them as per the instructions. I did see an initial drop in temperature down into 42-48 degrees just idling but still now about 58-62 degrees C under normal, semiloaded business use. However, when I stress test it using something like prime95 with 100% CPU utilization, within about 3 minutes I hit 90 degrees and from there can approach the 100 degree point, at which time I halt the test. When playing a relatively intense game (for this computer- a business setup) like Settlers 7, core temps tend to sit at 82 degrees for the CPU and discrete nVidia business graphics.

Running my original Dell BIOS diagnostic test with CPU stress test however, no longer gives the thermal overtemp warning and it no longer hits the 99 degree mark, now only peaking at about 86-87 degrees C. The heat coming off the fan is very warm therefore I believe I have good heat exchange between the CPU and the heat sink and the heat sink is blowing it off.

So what gives? Should I be worried/concerned or is that just the way this laptop runs?

I am starting to think this is just inherent in the design for having this processor with a relatively underengineered heat exchanger. Thoughts?

Thanks in advance.

 
Solution
Prime95 puts unrealistic stress on the CPU, so there's that, first off.

Arctic Silver 5 has a curing time, also, so it won't perform as well now as it will after 100 hours, give or take, of burn-in time.

My suggestion for the time being: Double check your paste application. Too much or too little can result in high temps. You may even want to reconsider that compound. Use an air compressor (or a can, if you must, though they're not ideal) to blow out the fan and the heat sink ─ and use something to prevent the span from spinning when you do this, so as to avoid damaging the bearings. Finally, check the heat pipe for any damage. If the pipe has any visible damage, it may not be transferring heat as well as it could be.

Beyond that, it...
Prime95 puts unrealistic stress on the CPU, so there's that, first off.

Arctic Silver 5 has a curing time, also, so it won't perform as well now as it will after 100 hours, give or take, of burn-in time.

My suggestion for the time being: Double check your paste application. Too much or too little can result in high temps. You may even want to reconsider that compound. Use an air compressor (or a can, if you must, though they're not ideal) to blow out the fan and the heat sink ─ and use something to prevent the span from spinning when you do this, so as to avoid damaging the bearings. Finally, check the heat pipe for any damage. If the pipe has any visible damage, it may not be transferring heat as well as it could be.

Beyond that, it may just be a design issue. You can add small copper RAM heatsinks to the copper plate over the CPU, and/or to the heat pipe, but they only do so much (and they may not even fit, depending on the headroom in the laptop).
 
Solution