Here's a closer look at what is happening with the alleged battery drain of the 15-inch Surface Book 2 during intense gaming.

Microsoft's Surface Book 2 has been on the market for a few weeks now, letting potential issues and limitations be discovered. While reviews for Surface Book 2, especially the 15-inch version (limited just to the U.S. market so far) have been overwhelmingly positive, it wouldn't be a Surface launch without at least some controversy.

In my review, I noted that in certain more extreme conditions, the 15-inch Surface Book 2 with its powerful NVIDIA GTX 1060 graphics card could drain the battery even when plugged into an outlet. The problem was first spotted by The Verge's Tom Warren before our review went to press, letting us verify the claim.

Since then, a lot of discussion around the topic has sprouted up on the internet, and today and I'll break down what seems to be happening and whether it's a big deal.

What exactly is happening?

When the Surface Book 2 15 is plugged in using the included Surface Connect power supply with the power plan slider is set to "Best Performance" (versus the default "Recommended") the battery may drain instead of recharging during intense activities. This drainage only occurs when pushing the CPU and GPU to the max for an extended duration in certain circumstances.

The problem becomes evident for some with a subset of high-end video games.

Microsoft says that after a few hours of drainage the GPU will throttle down letting the battery charge back up. In theory, the Surface Book 2 15 should never completely discharge at this stage leaving the user with a dead battery.

What is Best performance mode?

Best Performance is one of four settings found on modern Surface devices (the others being Battery saver, Recommended, and Better Performance). The settings have separate conditions, so you can set, for example, Battery saver when on battery, and Best Performance when plugged into an external power supply.

It was initially introduced in January 2017 to Windows Insiders and is part of the larger "Power Throttling" and "Power Slider" feature found in Windows 10.

From Microsoft:

With "Power Throttling," when background work is running, Windows places the CPU in its most energy efficient operating modes – work gets done, but the minimal possible battery is spent on that work.

When a user forces the slider to Best performance, this energy saving feature is disabled letting the processor max out.

Additionally, power throttling does not apply when the Surface is plugged into external power.

You can read more about Microsoft's Power Throttling and Power Slider in its detailed blog post on the subject.

What games are affected?

The answer to this one can be difficult, as it depends on the game's display settings.

Destiny 2 is cited as the most common example, but it's not across the board. Destiny 2 defaults to a weird 1282 x 728 resolution, instead of something at, or near, the native 3240 x 2160. Users cannot manually change that resolution either in the game settings – which is odd. Anti-aliasing, texture anisotropy, and texture quality are either on or set to near-max settings.

At these settings, with Best performance enabled and plugged in with the display brightness set to maximum, the Surface Book 2 15's battery can drain between five and 10 percent per hour.

Destiny 2 at native resolution on the Surface Book 2.

The Destiny 2 issue, however, is complicated. You can change the game settings, including its resolution, and even make them better while not getting battery drain.

In a related Reddit thread, I asked users to submit other games and scenarios where battery drain occurred.

One user noted that Fornite at "epic settings" drained around 10 percent over an hour. World of Tanks also reportedly drained around five percent an hour as did Middle Earth: Shadow of War at high settings with anti-aliasing configured to TAA.

Other games like LEGO Marvel Superheroes 2, Assassin's Creed Origins, PUBG, DOOM, and Overwatch, reportedly did not have any problems.

Why is this happening?

The included 102W AC adapter may not be large enough given extreme situations. Only about 95W goes to the Surface Book 2 as the remaining seven watts is used for the USB Type-A port for external charging.

In most cases – whether apps or even high-end games – the AC power is more than enough to run the Surface Book 2 and actively charge it. Most situations do not put the CPU and GPU at 100 percent usage at a constant pace for hours or even minutes at a time. However, when a user turns on Best performance, the system goes into a turbo-like mode, letting the Surface Book 2 15 drain more than it can pull from AC.

To be clear, you do not need to game while using Best performance, but obviously, gamers will want to try and max out the process and graphics cards for the best look and frames-per-second (FPS) performance. Likewise, even draining at 10 percent an hour, it would take five hours to deplete the system to 50 percent – which is a lot of gaming for one session.

Intel XTU shows how under duress Intel's CPU can down-regulate wattage to control for heat and reduce power draw.

There are other factors, too. If the room you are gaming is cold (below 70 degrees F, or 21 degrees C) there is less Power Limit throttling (PL1) from Intel. PL1 throttling reflects how hot the computer chassis gets. To prevent discomfort and burns, the wattage of the CPU is briefly reduced to let the system cool. Therefore, despite starting at 20 watts for the Core i7 processor, it cuts to between 12 watts and 15 watts over 20 minutes or more when running at 100 percent consistently.

By this logic, the colder the system is, the more power the CPU can draw (and get better long-term performance in a single session). Gaming in a warmer room will cause the thermal-design-point (TDP) to drop more rapidly, causing less power drain.

Again, this issue is complicated.

NVIDIA GeForce Experience is a must-have for gamers

One interesting solution is to use the NVIDIA GeForce Experience app for Windows.

Microsoft does not include the GeForce Experience app with any of its Surface devices. Instead, it pushes out new GeForce drivers through Windows Update after vetting them for issues. Users can bypass this with the Surface Book 2 by installing the GeForce Experience app. The risk is NVIDIA's drivers may cause problems or performance issues. Newer is not always better, so choose wisely if you install a new driver.

However, one significant benefit of the NVIDIA GeForce Experience app is that it automatically detects your hardware and games installed. After a quick analysis, it provides recommended graphics settings for your games when on AC power and battery. Users can then modify those settings even more in case they want to override them.

Using the GeForce Experience, users can alter Destiny 2 to run at higher resolutions including 2560 x 1600, or even native the native 3240 x 2160, instead of the paltry default 1282 x 728. Playing at 2560 x 1600 with anti-aliasing disabled and texture quality lower, Destiny 2 can still play at 60 FPS and look better. These settings can also make it, so the battery doesn't drain when plugged into the wall.

Any users who are looking to use the Surface Book 2 15 for gaming actively should install GeForce Experience. Not only does it allow you to improve the graphics, but it may very well address the battery drain problem.

Download NVIDIA GeForce Experience for Windows

The Surface Dock is not a good option

Another confounding issue is the optional Surface Dock. Unfortunately, the Surface Dock is a few years old now and supplies less power to the Surface Book 2 partially because it allocates some of the power for the other ports (four USB Type-A, Ethernet, and two DisplayPorts).

In other words, having multiple devices and displays connected to the Surface Dock may reduce the overall power to the Surface Book 2, which is usually fine for everyday computing, but when in Best performance, may not be enough.

Two power supplies at once is not possible

Users cannot use both the Type-C port for Surface Book 2 and a Surface Connect for charging at the same time. In all cases, the Surface Connect power supply will override the USB Type-C.

This practice is standard on all laptops, because various currents flowing to the computer board could be dangerous.

USB Type-C chargers also do not go over 100 watts, meaning they are not a viable solution (though you are free to use it as an alternative charger).

Conclusion and what should be done

The Surface Book 2 15 can drain the battery even when plugged into AC when certain conditions are met:

  • Best performance slider is enabled, overriding default Recommended.
  • Display brightness is 50 percent or higher.
  • Certain games when graphics are not set to match the hardware profile.
  • Cooler environments that let the CPU and GPU draw more power.
  • Using a Surface Dock with multiple devices connected.

To be clear, all or most of those conditions must be met – not just one – for the drainage to occur.

In my testing, and asking users for feedback, the overwhelming majority of video games do not have this problem. Those that do, like Destiny 2, can have their graphics settings changed (even improved) to prevent this from happening by using the GeForce Experience app.

As to what Microsoft can or should do two solutions come to mind:

  • Release an optional, larger power supply (AC charger).
  • Release a firmware update that reduces power draw from the GPU.

The first option seems the most obvious, but it's not without some issues. First, it will take months for a new AC charger to be designed, tested, approved, and pushed to retail.

Second, it doesn't make sense to ship a bulkier charger with Surface Book 2 since when using it as a standard PC – even under heavy duress – this drainage problem is a non-issue. Making consumers carry a bigger AC charger because some people use the Surface Book 2 as a heavy gaming laptop seems wrong.

Destiny 2 looks and plays great on the Surface Book 2 15.

A new charger likely won't be cheap either. Microsoft currently sells the 102W power supply for $73. A larger one in the 150W range will fetch more than that.

Microsoft could just patch the Surface Book 2 15 so that even when set to Best performance it can never draw more power than is coming into the system. But patching it now will likely anger many users. Given a choice to run the Surface Book 2 15 at max mode, power drainage be damned, or not, most power users would opt for the former choice. From Microsoft's perspective, however, capping the GPU's power drain would solve any customer complaints.

Update: The Surface Connect port can only accept up to 120W of power. While that is still below most gaming laptops with beefier 45W processors and 150W power supplies, it does provide some potential room for more overhead with a larger charger, were Microsoft to make one.

For now, Microsoft is giving users the option to run the Surface Book 2 15 without hindrance. While an optional more substantial power supply would be welcome, there is not much evidence that most users are experiencing this problem.

I game every day on the Surface Book 2 15, playing Destiny 2 and DOOM. Frankly, I'm still blown away playing a high-end AAA game at 2K resolution with vertical sync at 60 FPS on a Surface in 2017. It's awesome.

If you feel Surface Book 2 15 should never drain the battery under any circumstances (even when user-initiated), spend your cash elsewhere.