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Does using your laptop in bed cause it to overheat? We tested

People use laptops in all sorts of weird places. Part of a laptop’s appeal is portability and versatility, but you might notice that after a bedtime binge session, your sheets, or your lap, is pretty warm.

Modern computers, especially laptops, are built with a number of stopgaps between firing up a TV show and shutting down. You’d likely give up using your laptop because programs aren’t working long before it crashes. It keeps the temperature in check through a combination of fan speed control, power management, and throttling.

These techniques do a decent job keeping your laptop from melting, but how do they affect the user experience? When your next evening HBO GO session gets steamy, you’ll know exactly when to crack a window and cool off.

The test procedure

The first test we used was 7-Zip, a common utility for packing and unpacking .zip files. It has a built-in benchmarking utility that compresses and decompresses data which resembles an assortment of files. It places constant load on the processor, forcing it to fire up and run as quickly as it can.

The second utility is Futuremark’s 3DMark program. It’s a series of four graphical tests – short sequences that are increasingly difficult to render. These strain most components of a laptop, and of course place heavy load on the GPU, which is often the hottest chip in a modern PC.

To see how these tests impacted performance in different environments we ran them first with each laptop on a flat, solid desk, with no obstructions around it to prevent venting hot air or pulling in cool air.

Then we used a sleeping bag as a proxy for a situation where your laptop might not be able to vent well – like a bed, or your lap. We spread the sleeping bag out flat on a table, then set the laptop on top.

We used RealTemp to keep a time-stamped log of each core’s temperature, the GPU’s temperature, and the overall clock speed. In some cases, it was able to read the processor’s reported maximum temperature, and would also track if a core was OK or Hot. We tracked all of these statistics throughout both tests so we could chart the data and identify trends.

What happened, in a nutshell

Three laptops were tested; the Alienware 15, the Lenovo ThinkPad T450s, and the Asus UX305. Detailed results can be found in the links below, but if you want the summary, here’s what happened.

Surprisingly, the laptops did not experience significant slowdown when placed on the sleeping bag. Performance was identical more often than not. None of the laptops crashed or turned off automatically, not even when we ran the 3DMark benchmark to engage both the processor and the graphics chip.

That means system temperature does not significantly impact speed. Buying a laptop cooler under the theory that it may improve performance or stability seems a waste of money, and you can comfortably use a modern laptop in sub-optimal conditions without concern that it’ll overheat and reboot (or worse).

With that said, using the laptops on a sleeping bag did drastically increase external temperatures. At the worst, as with the Alienware 15, they shot high enough to be potentially hazardous. At best, they were high enough to be very uncomfortable.

Using a laptop on a surface that retains heat, or blocks the intake of cool air, will give you a case of sweaty palms. Some might argue it will decrease long-term durability — though that’s outside the scope of this test. But it won’t make your system slow to a crawl.

Next page: Alienware 15 testing

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