Battery Life, AC Draw, And Charge Rate
As we saw on the previous page, the GT70 Dragon Edition 2 employs a feature called NOS to utilize battery power when the system needs more than the AC adapter can provide, down to 30% charge. Be aware that, after a long gaming session, your battery might not be fully charged when you go to unplug from the wall.
Simply put, battery life is the overall capacity of the power source (in Wh) divided by draw. The GT70 comes with an 87 Wh battery, so an average 15 W load should give you almost six hours of run time. Increasing consumption by just 5 W cuts a full hour of use. At worst, you'll get a little less than one hour from the GT70 pulling 85 W from the battery. In exchange for accepting that wide range, the GT70 doesn't throttle down like other notebooks we've tested. You can decide whether to maximize battery life or performance, depending on what you're doing.
Intel's new Haswell-based Core i7-4930MX is capable of incredibly low power consumption at idle.
As you can see in the table above, the CPU's package power dips down to an amazingly low 1.772 W. The chip's four IA cores are only pulling .101 W. And that's really what the Haswell architecture is all about.
With the screen at 30% brightness, Wi-Fi off, and Windows set to the “Power Saver” scheme, the GT70 platform pulls 11 W. This is the lowest draw possible while still keeping the display's brightness at a useable level for indoor use. Full brightness adds about 4 W of consumption.
Browsing the Web with Wi-Fi enabled increases power use at 30% brightness to roughly 16 W. Watching 720p videos on YouTube registers about 15 W, while playing back Blu-ray content at 1920x1080 ups consumption to 23 W. Fully loading the CPU drains 60 W, while the GPU alone can pull 83 W. Maxing out power draw for the system yields a drain rate of 85 W/h.
The chart below shows the expected battery life in a variety of use scenarios.
Typing notes on the GT70 for six hours or more shouldn’t be a problem. Even if you add Web browsing to the mix, you should still see somewhere in the neighborhood of five hours. Expect more than four hours watching 720p content online. Two hours of gaming is a reasonable expectation if you're using the GeForce GTX 780M at its away-from-the-wall reduced performance settings.
AC Power Draw And Charge Rate
Charging the battery with the system powered down draws 52 W from the wall, while sitting idle in Windows with a fully-charged battery draws 34 W using the High Performance power profile. The charge rate is 40 W/h with Windows running, taking the total power draw up to 102 W.
Fully loading the GPU pulls a steady 141 W from the wall with a fully-charged battery, while the CPU alone draws 105 W. Keep in mind that each of these measurements also includes the platform components, including the chipset, Wi-Fi controller, display, and storage. Benchmarking various games varies power between 168 and 179 W, while a full load pulls a relatively steady 179 W.
If the battery drops under 30%, the system draws 201 W at the wall.
Apply a full load to either the CPU or GPU and the charge rate remains 40 W/h. Only when both subsystems are loaded down does the charge rate invert and become negative as NOS kicks in, draining the battery. Once the battery is depleted to 29%, the charge rate becomes zero.