Dell XPS 15 9560 heating problem

The CPU can heat up within a second under load if not cooled properly. 100 degC is the limit, but it is more common that it throttles down the clock than just shut down. Most likely you've got bad thermal paste between the CPU and the heatsink. This is a common problem with the XPS 15 because it has a powerful processor but a borderline heatsink due to the small thin case and because the assembly line at the factory seems works faster than what is feasible if one'd want good paste application and even QC of the thermals. 

Another thing to check is if the cooling system is stuffed with dust, or the heatpipe is defective. 

Thanks for the insight. Can there be a reason why it shuts down instead of throttling? Also is there a definitive way to check if the heat pipe is defective? Because right now Dell are asking me to pay INR 8000 ($120) to replace it without assuring me it will fix the issue

Sounds like a faulty temperature sensor is the top suspect.

@ejn63 Is the temperature sensor on the motherboard or on the heat sink assembly?

Maybe it is so bad that it feels it really needs to shut down. Or heats up so fast that the processor stops working before it manages to slow down the clock. Dunno. 

If still under warranty, they shouldn't ask you to pay anything, unless you have messed with it and broken it. 

It could also be the heatsink not attached properly, perhaps because the heatsink screws don't hold due to stripped screw threads (happens if one tightens the screw too much). 

The heatpipe is a tube with gas inside. If you bend it, it may crack and the gas escapes, so it can't deliver heat to the fins along the heatpipe anymore. If you load up the CPU with the case bottom open, the whole heatpipe should heat up very quickly. If the heatsink gets hot at the CPU but the ends of the heatpipes remain cool, it is likely not working. But if the heatpipe doesn't get hot even above the CPU, then the thermal contact to the CPU is likely the problem. It is likely difficult to test if a shutdown comes before much heat is released.  

The thermistor (temperature sensor) is part of the mainboard.

I wouldn't expect a thermal sensor to be a problem if the laptop shuts down under load.

I have a new Precision 5200 (shipped March 25, 2018) and have experienced numerous thermal shutdown events. They are triggered by Windows, not the BIOS. Regardless, the processor is getting up to 100 degrees Celsius, which is simply too hot. Research by me and Dell support has shown that running Photoshop can make this happen. Oddly, it's not so much when I am doing graphics-intensive operations as I/O-intensive operations, sometimes just opening or saving files. After numerous updates of the BIOS, chipset drivers, even Windows drivers, nothing seems to help. The only workaround so far is to disable CPU Turbo Mode (performance section) in the BIOS. This really **bleep** because isn't that why I paid big bucks for this system? Dell support's latest suggestion is to reinstall Windows. Having spent over 7 years in front-line support, I recognize this as a way to get out of acknowledging the real problem: defective design. Reinstalling Windows would take a VERY large amount of my personal time and I don't have faith that anything would change. I have to say that I am very dissatisfied with my system, not because of its performance, but because I feel like I've been ripped off by Dell, overcharged for something that I did not receive.

Most likely bad paste or the heatsink isn't attached well. If you have on-site support, ask Dell to send a tech. If not, you might be able to fix it yourself, following the Dell online service manual for removing/replacing the heatsink, and a couple of youtube laptop repasting guides. TG Kryonaut or Gelid EC paste is recommended, and you need a T5 screwdriver. The messiest part is removing old paste. Take care not to bend the heatpipe and strip screw threads by applying too much torque.