I've had my M15 since mid December and from the get go I've experienced thermal throttling.
Under games and stress tests, both HWInfo and Intel XTU would indicate temperatures would reach 100°c and thermal throttling.
Closer inspection showed this was mainly on half of the cores, 0, 2 and 4 in HWInfo.
After researching possible causes and finding that the thermal paste application could be a factor, I followed the Alienware process of repasting, but I just faced the same situation. I left it a week or so to give the paste chance to settle in, but the high temperatures in half the CPU cores remained. I tried another repaste just to make sure that wasn't an issue, and had the same problem.
Since then, I have had to undervolt and reduce the max turbo of the cores to keep the temperatures of the 3 hot cores under control.
So currently, the maximum temperatures I see are reasonable, but I am still left with half of the CPU cores being significantly hotter than the other half. The 3 hot cores will hit maximum temperatures in the region of 10-15°c higher than the cooler cores.
I've recently read and been advised that this could also be a symptom of an issue with the heatsink.
As the laptop is new and still under it's warranty, is it possible to have a replacement heatsink sent out? I am happy with doing the actual swap myself.
Yes, the difference in the temperatures displayed by the cores may be related to the heatsink, please adjust the tightness of the heatsink screws. If after this the issue continues, please send me a private message with the Service Tag so I can assist you further.
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I had the heatsink off just checking things and used some different thermal material when I put it back together.
My overall temperatures seem to have improved a little bit further, and when gaming, the cores are within maybe 5-6°c of each other. One particular core is always the hottest and one always the coolest heh. The temperature difference has always been greatest when the laptop was reaching over 85°c. It could just be that as it's running a bit cooler now the difference isn't as apparent.
I'll see how I get on with the for the time being.
One thing I did notice is that when I took the heatsink off, the fan nearest the GPU had a tiny bit of fluid on it that had transferred to the black area of the inside of the laptop. The part of the fan that has the label on (so the side that is essentially faced down when you are looking at it with the back of the laptop off) had a very fine film of some kind of liquid.
I had noticed this when I did a repaste previously. Or rather, I'd noticed a tiny spot that had been left on the laptop after I had removed the heatsink. I'd cleaned it off there, but I don't remember checking the fan itself and drying that out, so I guess it's something that may just have been on the fan?
Again, I'll keep a close eye (or should that be ear?) on the fan to make sure it's performing as it should.
So as mentioned, for the time being I'll see how I get on over the next month or so and then take it from there.