Back in the first half of 2015 Apple released the first version of the Apple Watch. The Apple Watch was a long-rumored product, often referred to as the iWatch before its release. At the time, it represented the best attempt that I had seen to provide a compelling smartwatch experience, but it was clearly a first generation product with flaws and shortcomings. It was not unlike the iPhone 2G or the iPad 1 in that regard, and for all the things it did well, there were other parts of the experience that really didn't deliver. While this shouldn't have been unexpected given the nature of first generation products, when a device is surrounded by so much hype for so many years, expectations can begin to run wild. On top of that, certain aspects like application performance were not up to the standards that are expected of a shipping product. In our review of the original Apple Watch we concluded that it was a good first attempt, but obviously flawed, and that ordinary consumers should wait for future iterations.

Jumping to the present, Apple is back with the second generation of the Apple Watch, the aptly named Apple Watch Series 2. The launch of Apple Watch Series 2 comes two years after the original announcement of the Apple Watch. Even when you consider the six month gap between the first Apple Watch's announcement and launch, this still represents a longer time between versions than the yearly cadence that we've come to expect for many other products. Having a product in the market for one and a half years is a good span of time to observe how users are making use of it, what features they are and aren't using, and what parts of the experience create friction. For a first generation product this kind of information is essential to make the necessary improvements in future iterations, as taking the product in the wrong direction could doom its future prospects entirely.

In addition to the improvements made in watchOS 3, Apple Watch Series 2 includes a number of hardware improvements. While one might think that specs are entirely irrelevant in a smartwatch, that actually couldn't be farther from the truth. Many of the issues with the original Apple Watch stem from various limitations in the hardware, particularly the slowness of the CPU and GPU. With Series 2 Apple has a chance to address many of these problems. I've compiled a table below with the specifications of both sizes of the original Apple Watch compared to their successors in Series 2.

  Apple Watch 38mm Apple Watch 42mm Apple Watch Series 2 38mm Apple Watch Series 2 42mm
SoC Apple S1
CPU: 520MHz Cortex A7
GPU: PowerVR Series5
Apple S2
CPU: 2 x 520MHz Cortex A7
GPU: PowerVR Series6 'Rogue'
Display 1.32" 272x340 OLED
450 nit brightness
1.5" 312x390 OLED
450 nit brightness
1.32" 272x340 OLED
1000 nit brightness
1.5" 312x390 OLED
1000 nit brightness
Size / Mass 38.6x33.3x10.5mm
Water Resistance IP67 "Splash proof" Water resistant up to 50 meters
Battery 0.78Whr 0.93Whr 1.03Whr 1.27Whr
Connectivity 2.4GHz 802.11 b/g/n + Bluetooth 4.0 2.4GHz 802.11 b/g/n + Bluetooth 4.0, GPS
Launch OS watchOS 1 watchOS 3
Price $349/549/10,000

The exterior design of the Apple Watch is clearly something that has been locked in for several generations. As you can see above, Apple has increased the size of watch slightly with Series 2, but it's not something that can really be noticed in practice, and it doesn't break compatibility with existing watch bands which is good news for anyone upgrading from the original Apple Watch. The water resistance of the case is also greatly improved, having gone from the vague "splash proof" rating in the original model to being rated for water resistance up to a depth of 50 meters. The jewelry-focused gold Edition models are also gone, replaced by a ceramic model at 10% of the price.

Apple S2. Source: Chipworks

Internally, Apple has made some key changes that have a profound impact on the user experience. The most obvious is the new chip powering the watch. Apple's S2 SiP now has a dual core processor and an improved GPU. Apple rates it as 50% faster for CPU-bound workloads, and twice as fast for GPU-bound workloads. Apple has been known to state smaller gains than the theoretical doubling of performance when moving from a single core to a dual core CPU, and based on some investigation it appears that Apple has simply doubled up on CPU cores, adding another 520MHz ARM Cortex-A7 core to complement the first. Single-core/single-threaded performance appears unchanged, so getting better performance out of the S2 means putting that second core to work.

As for the GPU, this is much harder to pin down. It's most likely the case that the Apple S1 SiP used the PowerVR GX5300 GPU, and I suspect that Apple is using Imagination Technologies' newer PowerVR "Rogue" architecture - likely some variant of the G6020 GPU - in the Apple S2. I say variant, as Apple's recent work with GPUs in their SoCs could be indicative that Apple does not need to use Imagination's reference design.

Like the S1, the S2 is paired with 512MB of RAM. It's again hard to verify that this is LPDDR3 memory so I've marked that as speculative in the chart. I did want to note that other sources have reported 1GB of RAM for the S2, but I am fairly sure that this is not the case. iOS, and subsequently watchOS, provides an API for developers to query the number of CPU cores and amount of RAM available in the device, and it confirms that Apple has not increased the amount of RAM available in Apple Watch Series 2.

Apple Watch Series 2 42mm battery. Source: Chipworks

Another major internal change is the battery. Apple has increased the battery capacity on the 38mm model by 32%, and the 42mm model by 36%. This will do well to offset the increased power requirements with the introduction of GPS in the Apple S2 SiP. Apple still rates the battery life for Series 2 at eighteen hours, and in my experience you could wear the watch for two days before having to recharge as long as you don't do too many workouts. However, I still charge it each night, and we're still not close to the point where you can wear a smartwatch for a week with both daytime tracking and sleep tracking.

The last major hardware change in Series 2 is the display. Apple still uses a 326ppi OLED panel on both models, with the 38mm casing having a 1.32" display and the 42mm casing being a larger 1.5" display. What has changed is the peak brightness. One of the issues I encountered with the original Apple Watch was an inability to see what was on the screen when there was heavy glare. This was even more pronounced on the steel versions that use sapphire glass, which is more reflective than the Ion-X glass on the aluminum models. Apple rated the original Apple Watch displays at 450 nits of brightness, and with Series 2 they claim to have increased this to 1000 nits, which is an enormous improvement.

Given that the Apple Watch is still a relatively new product, it's likely that many people have still not interacted with one before. Because of that, and the very personal nature of watches, it's worth covering the design in more detail, and so I'll talk about that next.

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  • johnny-12 - Tuesday, December 20, 2016 - link

    You didn't mention anything about the Apple Watch Series 1 (original watch with S2 SiP)
  • amdwilliam1985 - Tuesday, December 20, 2016 - link

    Where is the kiss-ass Macbook Pro review?
    Apple has "fixed" the battery problems, now update your results and praise the gods. (I know Anandtech can't do a "bad" Apple product review ;)

    On a more serious note, please do a battery life comparison between 13" non-touch vs 13" touch bar, I want to see the battery hit and the performance trade off. I don't care if it only lasts 3 hours, or breath-taking break through (30% improvement aka 4h), I just want to know the trade off (in relative terms) so I know what I'm buying into. I'm sure there are many people in the same boat.
  • amdwilliam1985 - Tuesday, December 20, 2016 - link

    Bloomberg: How Apple Alienated Mac Loyalists.

    RIP Mac
  • amdwilliam1985 - Thursday, December 22, 2016 - link

    Oh no, Consumer Report got bought by M$ and/Google too.

    Man, the "whole world" is picking against the "underdog", Apple T_T
    Don't worry, Anandtech is here to kiss ass and save the day ;) There are not enough money in the world that M$ and Google can spend to persuade Anandtech.

    Jokes aside, can we expect Macbook Pro reviews coming soon? Please...
    Christmas gift?

    I have to buy Mac, because I need xcode to write iOS apps.
    Don't want to deal with linux, I don't have the time and energy.
  • serendip - Tuesday, December 20, 2016 - link

    A lot of commenters dissing smartwatches should use a smartwatch for a few weeks before commenting. I know because I thought wearables were pointless until I got a Pebble. Now I can't ever go back to a normal dumb watch. It was a revelation to have a tiny computer strapped with so many apps strapped to my wrist. The Apple Watch is even more amazing because of the deep iPhone integration and its sensor suite.

    And lastly, RIP Pebble, I hope the tech lives on somehow. I'll be using mine until it stops working. The always-on LCD makes it feel like a normal watch yet I can get by with charging it every 4-5 days, not like the daily charging needed by other smartwatches. Maybe Apple needs to have an always-on OLED screen like with Nokia's Sleeping Screen app on Symbian.
  • mobutu - Tuesday, December 20, 2016 - link

    smartwatch is dead anyway
  • hasseb64 - Wednesday, December 21, 2016 - link

    Simply: Another useless product that needs constant charging.
    If you have money and want something big on your arm, buy a Swiss made watch, at least you look good with that on!
  • FunBunny2 - Wednesday, December 21, 2016 - link

    I don't know. at some point folks, producers and consumers, will have to admit that the limiting point of all portable devices (watches, phones, laptops, etc.) is power. and there hasn't been a meaningful increment (much less a doubling) in power density in a battery in decades. until someone is smart enough to invent a new atom, the wall is staring you in the face. controlling a chip as node size shrinks, while reducing power demand by a bit, will in and of itself demand more circuits and power. WYSIWYG.
  • zeeBomb - Wednesday, December 21, 2016 - link

    So... What's different?
  • amdwilliam1985 - Thursday, December 22, 2016 - link

    Everything is different, the world has been turned upside down if you're an Apple fans.
    If you're not, then move on along, nothing much to see here.

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