Apple Watch Series 3 vs. Series 4 – Should You Upgrade?

Last Updated: Nov 22, 2022

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The Apple Watch Series 4, together with the iPhone XR was arguably the most exciting new device Apple announced at the September 2018 keynote. To help you understand what the differences are between the Apple Watch Series 4 vs. Series 3, here is an in-depth comparison.

Even though I already owned an Apple Watch Series 3 GPS + Cellular, I decided to upgrade to find out if the new hardware would be worth the asking price.

Update: In September 2019, Apple announced the Series 5 and I decided to buy it. Learn more here.

Apple Watch Models

The new Apple Watch Series 4 is available as a GPS-only and GPS + Cellular model. Beyond the type of wireless connectivity, you can choose between a silver aluminum, space gray aluminum, and a stainless steel case, as well as various band types and colors.

Apple also continued its partnership with Nike and Hermès by offering the following, branded models:

  • Apple Watch Hermès
  • Apple Watch Nike+

Note that Apple appeared to have discontinued the high-end Edition models, including the gold and ceramic versions. While I never cared for an 18 karat gold Apple Watch, I liked the white ceramic body Apple offered with the Series 3. I also know that many fans were looking forward to a black ceramic timekeeper they thought Apple had in the works.

Apple Watch Series 4 Pros and Cons

  • A 30% larger screen and thinner body
  • Improved heart rate sensor with EKG/ECG
  • Bluetooth 5.0
  • Fall Detection
  • Faster CPU
  • Compatibility with my old bands and straps
  • No always-on screen option
  • Expensive for a gadget you may upgrade every year

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Case and Display

Difference in case and screen size between Series 4 a Series 3
The difference in the case and screen size between Series 4 a Series 3

One of the things you’ll immediately notice with the Apple Watch Series 4 is the bigger display, rounded corners, and thinner bezels. The smaller watch used to have a 38mm case, offering 563 square millimeters of a display area. In Series 4, the smaller clock now has a 40mm case and 759 sq mm of a display area. That’s larger than what the older model had.

As a result of those improvements, watchOS, Apple’s wearable operating system can display much more information, such as additional complications or richer notifications. Apple has also managed to reduce the thickness of the Apple Watch from 11.4 to 10.7 millimeter.

From a display technology perspective, the new Apple Watch features a Low-Temperature Polycrystalline Oxide (LTPO) OLED panel, which combines both LTPS TFTs and Oxide TFTs. These panels are more difficult to manufacture, but they are 5-15% more power efficient.

What’s great for all current Apple Watch owners is that the Apple Watch Series 4 is compatible with all of the old bands! That’s great news for me because I have collected quite a few leather straps and workout bands.

When I ordered the Series 3 last year, I chose the olive green Sport Loop because Apple didn’t offer the Sport Loop in black. This year, when I placed the order for the Series 4, Apple offered it in black as well! So I’m super excited to finally get the band I love in the color I like.

One thing I didn’t notice while watching Apple’s keynote was that the company evidently discontinued the “Apple Watch Edition.” I understand why Apple stopped selling the $18k Edition in yellow gold, but I thought the much less expensive Ceramic watch was a reasonable compromise between luxury and affordability. I guess Apple didn’t sell enough of those either to warrant keeping them around.

Heart Rate Sensor

Apple Watch Series 4 can record an ECG/EKG
Apple Watch Series 4 can record an ECG/EKG

One of the most exciting new features in the Apple Watch Series 4 is the new electrical heart rate sensor that is capable of detecting atrial fibrillation (AFib). Starting later this year, you will also be able to record an electrocardiogram (ECG) right from your wrist.

In case you wonder, EKG and ECG are two acronyms that have the same meaning, but EKG comes from the German word Kardiogramm.

What’s also new is that Apple has received FDA clearance for both its ECG and AFib detection capabilities.

Health Features

Unfortunately, the sampling rate of Apple’s heart rate sensor is still relatively low if you are not in workout mode. That, combined with battery limitations, means that you cannot use the Apple Watch for proper sleep and recovery tracking. Also missing is in-depth reporting and analysis via the Health app.

For example, while the watch records your heart rate variability (HRV), it doesn’t put it into the context of recovery or sleep performance.

If such metrics are as important to you as it is to me, you have to rely on a third-party fitness tracker. I recently reviewed the WHOOP fitness strap which fills the gaps left by Apple’s timepiece.


Apple S4 System-on-a-Chip (SOC) featuring two Tempest Cores
Apple S4 System-on-a-Chip (SOC) featuring two Tempest Cores

The Apple Watch Series 4 features a dual-core S4 processor, which is up to twice as fast as the S3 that Apple used in the previous generation Apple Watch.

The Series 4 also marks the jump to a 64-bit processor, but interestingly enough, Apple decided to go with an ARM64 architecture with 32-bit pointers. Some engineers speculated that Apple’s decision makes it possible to use ARMv8 instructions with lower memory pressure. Also interesting is that the two “Tempest” CPU cores in the Apple Watch are similar to the “efficiency cores” in the new iPhone models.

More importantly, however, is the inclusion of Apple’s W3 wireless chip in Series 4, which I suspect Apple will also put into the second-generation AirPods. According to The Verge, the W3 is the same chip as the W2 but with Bluetooth 5.o support.

Improved Sensors

Fall Detection in the new Apple Watch Series 4
Fall Detection in the new Apple Watch Series 4

Apple has made improvements to various sensors, including the:

  • Accelerometer
  • Gyroscope

These improvements were necessary to add “Fall Detection” to the Apple Watch Series 4. Fall detection is an incredibly useful feature, especially for the elderly, to detect if the wearer fell and may need medical attention.

If the watch detects a fall, it automatically offers to call for help and notify emergency contacts. Even better, it can make those calls automatically for you, if the watch doesn’t detect movement for five minutes after you fell.

Battery Life

Apple Watch Battery Life (Source Techradar.com)
Apple Watch Battery Life (Source Techradar.com)

According to Apple, the Series 4 features the same all-day battery life as the Series 3. While the technical specifications call for a battery life of up to 18 hours, my Apple Watch Series 3 usually lasts much longer than that.

Wireless Connectivity

The Apple Watch Series 4 features almost the same wireless specs as the previous model except for Bluetooth 5.0. The upgrade to the latest BT technology should result in a more reliable and secure connection to other devices, such as your iPhone, wireless headphones, heart rate monitors and more.

Miscellaneous Improvements

The digital crown now features haptic feedback
The digital crown now features haptic feedback

One thing I didn’t like on my Apple Watch Series 3 (Cellular) is that ugly red dot on the digital crown. Fortunately, the designers at Apple must have felt the same way because they replaced the solid dot with a more subtle red ring.

Apple has improved its haptic sensor by adding haptic feedback when you turn the crown to enhance the user experience while scrolling through screens.

Both the GPS and GPS + Cellular models of the Series 4 now have 16GB of storage. In Series 3, the GPS model had only 8GB. As a result, you can now download more apps and have more music on your Apple Watch for offline listening.

Apple has made the back of all Apple Watch Series 4 models of ceramic and sapphire crystal. The back of the previous generation GPS model was made from a composite material. I suspect the electrical heart rate sensor to be the reason for this improvement.

watchOS 5 Improvements

While many of the new features I described above are limited to the Apple Watch Series 4, Apple has also made a ton of improvements to watchOS. The good news is that even owners of older models can benefit from those and examples include:

  • Walkie Talkie (Apple Watch Series 1 or newer)
  • Additional workout types (i.e., Yoga or hiking)
  • Personalized coaching
  • Activity competitions
  • Automatic workout detection
  • Advanced running features (i.e., Pace alerts and cadence)
  • Smarter Siri watch face
  • Grouped notifications
  • Siri Raise to Speak (Apple Watch Series 3 or newer)

Comparison Table

If you would like to download a PDF copy of this table, click here.

Series 4Series 3
Case Size44mm / 40mm42mm / 38mm
MaterialAluminium, Stainless SteelAluminium, Stainless Steel, Ceramic
Display Size977 sq mm / 759 sq mm740 sq mm / 563 sq mm
Brightness1,000 nits1,000 nits
CPUApple S4Apple S3
CPU Architecture64-bit Dual-Core32-bit Dual-Core
Wireless ChipApple W3Apple W2
Heart Rate SensorOptical (2nd Gen)Optical
Fall Detection
AccelerometerUp to 32 G-ForcesUp to 16 G-Forces
SensorsBuilt-in GPS, GLONASS, Galileo, and QZSSBuilt-in GPS, GLONASS, Galileo, and QZSS
Water Resistant50 meters50 meters
Barometric Altimeter
Ambient Light Sensor
Capacity16 GB16 / 8 GB
Digital CrownWith Haptic Feedback
Fits All Watchbands
ColorsSilver, Space Black, Space Gray, GoldSilver, Space Black, Space Gray, Gold
Material (Back)Ceramic and Sapphire CrystalCeramic and Sapphire Crystal / Composite
Cellular ConnectivityLTE and UTMSLTE and UTMS
Wi-Fi802.11b/g/n 2.4GHz802.11b/g/n 2.4GHz
Battery LifeUp to 18 HoursUp to 18 Hours
SpeakerImproved (Louder)
MicrophoneImproved (Less Echo)
MSRP$399 (GPS) / $499 (GPS + Cellular)$279 (GPS) / $379 (GPS + Cellular)

Apple Watch Series 4 vs. Series 3 – Conclusion

Overall, the Apple Watch Series 4 is packed with enough new features and improvements to warrant an upgrade from Series 3. The Series 4 model I ordered is over $500, including tax, which is a lot of money for a wearable. But I can sell my Series 3 (GPS + Cellular) for at least $250 and that makes the price of the new model more reasonable.

Now I’d like to hear from you! Are you going to buy your first Apple Watch or are you thinking of upgrading from a previous model? If so, let me know by leaving a comment below!

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