Being introduced for the first time with the GeForce GTX 800M series is Battery Boost technology, a method that NVIDIA has developed to extend the battery life of notebooks while gaming.
Using a combination of GeForce Experience and Optimus, Battery Boost is enabled automatically when you start a game on your laptop in battery mode. (As a side note, if you unplug your machine after starting a game, the battery savings will not be put into affect!)
Even though NVIDIA is being somewhat cagey about what exactly Battery Boost is doing, we can come up with some pretty good guesses. First and foremost, the battery saving technology is using frame rate limiting, a feature that has existed with desktop GeForce GPUs since the introduction of Kepler. While Kepler (and Maxwell) GPUs were built with very granular power states and clock rates to enable GPU Boost, the same features are being used to lower performance / power consumption to extend battery life.
NVIDIA by default will target a 30 FPS mark for "playable" frame rates when in battery mode although this is adjustable by the user inside GeForce Experience.
But there is more going on under the hood with Battery Boost than just frame rate. NVIDIA calls this a "driver level governor" that can operate the "CPU, GPU and memory at peak efficiency." NVIDIA did admit that they are not adjusting CPU power states at all so that leaves us with more questions than answers. The driver could be request data from the processor in less frequent intervals or lowering compile times for shaders in real-time or it could be something else entirely. But based on the graphic above, NVIDIA is definitely doing more than just lowering GPU clock speeds to meet the 30 FPS frame rate limit.
The first iteration of GeForce Experience with support for Battery Boost will use the same image quality settings for battery-based and plugged-in gaming though, coming later this month, NVIDIA will offer up an additional profile. It will allow users to have different settings (lower resolution, less AA) while running on battery power to help further increase usable gaming time.
NVIDIA provided some examples since we hadn't wrapped our hands around a working notebook with Battery Boost integrated yet. Borderlands 2, at 1920×1080 and high presets, saw a 52% improvement in battery life while gaming. What we don't see is the frame rate and experience differences between the two modes.
Bioshock Infinite with a GeForce GTX 880M sees as much as 50% better gaming battery life with Battery Boost.
The big winner though is League of Legends, that at 1080p with Very High settings, saw a 97% increase in playable battery life on the GTX 860M!
Along with Battery Boost, that is ONLY coming to the GeForce GTX 800M GPUs, NVIDIA is bringing some other features, currently exclusive to the desktop, to mobile gamers.
ShadowPlay gives users the ability record in-game footage with minimal impact on performance using the encoding power of the GeForce GPU. GameStream allows gamers to stream PC games to select devices like NVIDIA SHIELD over their home network. Both features were previously limited to desktop users even when we knew that the compute power of many mobile GPUs was more than capable of handling the workload. Now, with the release of a pending update to GeForce Experience coming later in March, GeForce GTX 700M and GTX 800M products will be able to run both.
Though there are several aspects to today's announcement of the GeForce 800M series of mobility GPUs that are only worth a passing glance (rebrands), the inclusion of Maxwell GPUs with the GTX 860M, as well as the 840M and 830M, brings some spice to the mobile gaming market. I still believe that the confusion of having both Kepler and Maxwell options with the same naming scheme will aggravate and annoy OEMs as well as the users smart enough to know which one they want.
Battery Boost is an interesting technology that I am eager to test out once we get our hands on a notebook that integrates it. Gaming battery life has usually been something we tended to laugh off with most machines but it's possible now that NVIDIA's focus will push reviewers (like us) and OEMs to take note (and improve upon) that aspect of performance. I still have doubts about the experience effects of frame rate limiting, and how that is balanced against battery life, but we can address those after some hands on time later this month.
Though we didn't see a flagship Maxwell part released for mobile devices that we kind of hoped, NVIDIA continues to push forward with discrete graphics innovation for notebooks and that is something we can all get behind.