Inside the GS40 are two small blower fans attached to small heatsinks and heatpipes, designed to cool the 45W CPU and 75W GPU respectively. Although there are two fans and heatskins, both halves of the cooling solution are actually joined via a single heatpipe. The CPU side only gets one vent, with air pushed directly out the back, while GPU side sees air vented from the back and right-hand side. In both cases, air intake is on the bottom only, so it’s not a good idea to block the underside of the laptop.
The combined 120W of thermal load sees the GS40 reach warm but not unreasonable surface temperatures. The keyboard reached no hotter than 41°C during a sustained gaming session, falling to around 37°C near the left-side gaming keys, which is right on what I’d consider to be the limit for comfortable gaming. Thermal performance on the underside of the laptop is not great. There are two distinct hotspots corresponding to the CPU and GPU that easily exceed 60°C during load, which you certainly wouldn’t want to touch if you’re gaming on your lap. Luckily this heat is well dissipated through the rest of the chassis and cooling solution, so the majority of the underside sits at or below 45°C.
At idle, both thermal and noise performance is decent, with the laptop usually turning both its fans off, passively cooling the CPU and GPU. Temperatures while passively cooling the 45W CPU are around 36°C or less throughout most of the laptop’s body, although there are some hotter spots, and the fan will engage as soon as you attempt a slightly more intensive workload. The noise profile from the dual fan cooler during load is similar to a jet engine, like most gaming laptops with small fans for cooling. However, in the case of the G40, the fans aren’t so loud or annoying that you can easily hear them over in-game audio from the laptop’s speakers. Don’t get me wrong - the cooling solution is certainly noisy, and the laptop’s speakers aren’t particularly powerful - but it lacks the piercing high-pitched whine of competing laptops, which helps reduce the annoyance factor of the cooler. Inside the MSI GS40 Phantom 6QE is a 61.25 Wh non-removable lithium-ion battery, coincidentally the same size as the battery in the Gigabyte P34W v5. The battery is not particularly large for a laptop of this size, which doesn’t bode well for battery life.