Playing With Power: A Look At Nintendo Switch Power Consum…

Last week was of course the launch of Nintendo’s eagerly anticipated Switch console. The company’s latest handheld console, the Switch is a bit of an odd duck in pretty much every way. It departs from Nintendo’s traditional and well-established clamshell design in favor of a larger tablet, and under the hood Nintendo has stepped away from their typical highly-custom low-power SoC in favor of a rather powerful Tegra design from NVIDIA. Given that the 3DS was essentially an ARMv6 + OpenGL ES 1.x device, I can’t overstate just how significant of a jump this is under the hood in going to the ARMv8 + OpenGL ES 3.2/Vulkan class Tegra SoC. Nintendo has essentially jumped forward 10 years in mobile technology in a single generation.

In any case, in between benchmark runs for other projects over the weekend, I’ve been poking and prodding at the Switch to see if there was anything interesting to find. Nintendo still hasn’t disclosed low-level specifications – nor was I expecting them to – so Digital Foundry’s unofficial analysis remains the best we’re going to see for now. And for a look at the physical layer, iFixit has once again done another one of their wonderful teardowns with the Switch, identifying many of its supporting chips and confirming that the “HD Rumble” motor is indeed a linear actuator, though oddly enough one that works on its short axis instead of its long axis.

Meanwhile thanks to some proxy shenanigans, I’ve been able to get the Switch to run some of our JavaScript benchmarks. The console ships with an integrated, stripped-down version of WebKit for use with various web services, though there’s no proper web browser exposed to the user. However this stripped-down browser clearly isn’t meant for full-on web browsing; with a Kraken 1.1 run time of 172-thousand milliseconds (~2% the throughput of a Tegra-based Pixel C), I suspect the browser isn’t even doing native JS compilation and instead is doing interpretation. So at least for the moment, there’s not much in the way of meaningful benchmarking that can be done.

Nintendo Switch: Playing With Power

However one area that I have had some success with is power measurement. And this is another area where the Switch is a bit of an odd duck, leading to some confusion around the Web judging from some of the comment posts I’ve seen elsewhere. USB Type-C has been shipping in devices for a couple of years now, so it’s hardly a new standard, but given the slow upgrade cycle of PCs and smartphones it still isn’t an interface that the majority of consumers out there have dealt with. Furthermore due to its use case as a game console, the Switch is unlike any other USB Type-C device out there (more on this in a second). So I opted to spend some time profiling the device’s power consumption, in order to shed some light on what to expect.

First off then, what makes the Switch such an odd duck here? This is merely anecdotal, but one of the big hang-ups I’m seeing is that a lot of people aren’t accustomed to using what’s essentially a high-power tablet that’s running at fill-tilt at all times. The secret to the long battery life (and clockspeed turboing) of the iPad and other tablets relative to their size is that they spend the vast majority of their time idling. It doesn’t take a lot of energy at the SoC level to display text or watch a video; the SoC is only called on in short bursts to render something before it goes back to sleep. The Switch, on the other hand, spends the vast majority of its time gaming, meaning the SoC is frequently in its highest power state.

The fact that the Switch lives most of its life at two extremes – asleep or running at full speed – means that it’s a bit unintuitive what to expect from it when it comes to power consumption. Or, for that matter, what to expect when charging it. So, in what’s ultimately an excuse for me to play with a new toy, Satechi’s USB Type-C power meter, I’ve been profiling the power consumption between the Switch and its AC adapter. As a bit of a heads up, the Satechi meter isn’t perfect – the device has to draw a bit of power itself – so if I wanted to be more rigorous about this I’d need to do a proper multimeter setup. But for some quick testing, Satechi’s meter works well enough, especially given the fact that its own power consumption is a drop in the bucket compared to the Switch’s.

Finally, looking at the specifications of the Switch, there are two numbers I want to point out. The first is the power rating of the console’s AC adapter: 15V @ 2.6A, or 39 Watts. This power adapter is quite powerful, more powerful in fact than the 29W adapter Apple includes with the modern 12-inch MacBook. Meanwhile the second number I want to point out is stamped into the bottom of the dock, and that’s the output power rating of the USB-C male port built into said dock for the Switch to connect to. It’s only rated for 15V @ 1.2A, for a total of 18W.

The difference between the two is due to the fact that the Switch dock itself plays host to 3 USB Type-A ports, including a USB 3.0 port on the rear. As a result the power adapter for the Switch apparently needed to be quite a bit oversized to ensure that it never faces a load larger than it can handle. Besides running the Switch, it also potentially needs to be able to power a USB hard drive and charge a couple of Pro Controllers, all of which can add up quickly. Consequently it’s the Dock’s output rating of 18W that’s the more meaningful number as far as Nintendo’s own specifications go.

The Switch’s Dock (Image Courtesy iFixit)

Anyhow, that’s enough rambling on background information. Let’s look at the power numbers.

Power Consumption: Docked

To start things off, I wanted to see how much power the Switch drew while docked. This is broken down to a fully charged Switch – so that we can infer just how much power the Switch system (sans display) is drawing to run – and then again with a Switch under 20% battery capacity so that it needs to charge as well. All of this is measured by letting the Switch load from a save in The Legend of Zelda: Breath of the Wild, which according to Nintendo’s battery life estimates, is likely the most power-intensive of the launch games. The following values are all averages over 2 minutes.

With the Switch charged and running Zelda in its docked configuration, it’s drawing on average 11 Watts of power. The dock itself is consuming a bit of this energy to power its DisplayPort to HDMI converter, but it’s safe to assume that virtually all of that power is going to the Switch itself. And while I didn’t pull noise measurements on the Switch, while the console’s fan was active, it was holding at a fairly low speed, judging from the softness of the sound.

Letting the Switch discharge and loading up Zelda again finds that power consumption has (unsurprisingly) increased, to 15.7W. Throwing on the partially discharged joy-cons bumps that up a bit further to 16.5W, coming fairly close to the official 18W limit of the dock. One thing to keep in mind here is that if we subtract out the 11W from earlier, we only end up with 4.7W left to charge the Switch’s battery.

Finally, if we turn the console off and just let it charge, we find that the Switch + dock draws 9.8W. This is nearly twice the amount of leftover power the Switch had available to charge its battery with when it was docked and turned on. Meanwhile, adding the joy-cons to the mix to recharge as well brings the total power consumption up to 12.1W. The takeaway? The Switch can recharge fairly quickly, but only if it’s not turned on. If it is on, it will still recharge in the dock, but at around half the rate.

Power Consumption: Undocked

The next question of course is how this compares to power consumption when undocked, so let’s find out.

Starting off again with a fully-charged Switch, with the display at minimum brightness we’re down to 7.1W, or 3.9W less than when it was docked. Considering that some of this power is going to screen and that we can’t…