Noise, Heat and Battery Life
Before I discuss the battery life of the Alienware 15, it's worth mentioning the laptop's cooling system. For one, when the GTX 980M and i7-4710HQ kick in to upper gear, the dual cooling fans aren't exactly quiet. When gaming using the internal speakers in the Alienware 15 at a reasonable volume, the sound of the cooling fans is still audible in the background, which isn't a great result (unless you're gaming with headphones and don't care).
Temperature wise, during an intense stretch of gaming where the fans are fired up, the CPU reaches around 80°C and the GPU 72°C, which isn't too bad considering the high TDPs of both components. After lengthy sessions of gaming, the top few rows of the keyboard and the plastic above can get reasonably warm, up to 45°C in some spots, though I never found it too warm to handle during hours of gaming.
As for battery life, the Alienware 15 comes with an internal 92 Wh battery that probably won't deliver excellent stamina considering the powerful internal components. Let's check out the benchmarks
As you'll see from the charts above, battery life is slightly better than the Alienware 13, but still reasonably poor overall. This laptop isn't meant for web browsing on the go, which is why Alienware feels content with a Wi-Fi browsing result of just four hours, despite the massive battery.
When gaming on battery, you could reasonably expect up to 80 minutes at a reasonable brightness level in an intensive game, which means you'll probably want to bring along the charger to any gaming session. Performance is also cut in half when not connected to the wall, so keep that in mind whenever you're only on battery.