Perhaps the first thing about Series 4 is the larger screen, which is up to 35 percent larger than the Series 3. Specifically, the larger 42mm Series 3 and 44mm Series 4 models compare, Series 3 has a display area at 740 sqm, while the series 4 has a display area of 977 sqm. This means that the 44mm Series 4 display is 32 percent greater than the 42mm Series 3.
Similarly, for the smaller models, the 38mm Series 3 has a display area of 563 sqm, compared to the 40mm Series 4 with a display area of 759 sqm. This results in an increase of 35 percent of the screen size between generations. In essence, this means that the Series 4 packs more screen into what is almost the same as Series 3, with slimmer features that are somewhat visually similar to the rounded corners of the iPhone X and iPhone XS.
The enhanced viewing range also gives increased resolution, with 44mm Series 4 including 368×448 pixels, compared with 312×390 on 42mm Series 3. 40mm Series 4 has 324×394 pixels while 38mm Series 3 has 272×340 pixels. Thanks to all of these changes, the app icons and types are now bigger and easier to read too.
Although the screen sizes are increased, there are small changes in the actual size of the case for Apple Watch Series 4, despite the new measurements. 38mm in Series 3 and earlier has become 40mm and 42mm in Series 3 and has previously been 44mm, with both of these numbers representing the height of the Apple Watch Series 4 case.
This is a change that should not be too noticeable unless you compare the Series 4 with a previous generation model side by side. And do not worry about this update that affects your current bandwidth, as Apple made it clear during yesterday's main speech that all previous Apple Watch tapes fits the Series 4 case.
When looking at the thinness, the Apple Watch Series 4 is just under 1mm slimmer compared to Series 3. Series 4 measures 10.7mm thin compared to 11.4mm thin for Series 3.
As expected with an Apple update, Series 4 has received an amplified processor in the form of 64-bit dual-core S4 processor.
Apple says that this is up to two times faster than the S3 processor found on Series 3, so that the Series 4 gets faster when you open apps and perform other features.
Exclusive to Apple Watch Series 4 is a collection of watch faces that utilize the expanded screens to show as many as eight complications.
These complications have been improved to be more precise and provide more information, thanks to the increased viewing range.
There are also a few watch faces that will respond uniquely to the edges of the Series 4 screen, such as steam, liquid metal and fire and water.
For the first time in a portable device, you will be able to take a full ECG reading on Apple Watch Series 4. Using electrodes embedded in Digital Crown and a new electrical heart rate sensor in the back crystal, an ECG included -app will perform a reading when touching the digital crown and holding it for 30 seconds.
The app can classify if your heart beats in a normal pattern or if there are signs of atrial fibrillation, which may be suggested by potential health complications. You can save the ECG recordings in the iOS Health app and create a PDF file to share with your doctor. While Apple Watch has always been able to track heart rate, the ECG app is an important update to Apple's portable line.
The ECG app will be added to Apple Watch Series 4 later this year and will only be available to customers in the US at launch.
Below is a quick list of features that are new and exclusive to Apple Watch Series 4, which are not available on Series 3 and earlier devices. We have also listed everything that has not changed further down, a noticeable constant being 18 hours battery life.
Changes between Series 3 and Series 4:
- Series 4 now contains Haptic feedback on the digital crown
- The black ceramic and crystal crystal tray allows radio waves to pass through the 4 better cellular service
- The Speaker of Series 4 is ] 50 percent higher
- Apple has moved the microphone to reduce echo for better sound quality on the receiving side of phone calls
- With a new accelerometer and gyroscope, the 4-channel can detect if you fall down and ask if emergency services are to be notified
- The improved accelerometer can measure up to 32g power increased from up to 16g power in series 3
- Series 4 has Apple's new W3 wireless chip instead of the previous generation W2
- Connection enhancements also include new Bluetooth 5.0 up from 4.2 in Series 3
- Now has already le models 16GB storage capacity es instead of only GPS + Cellular on Series 3
No changes between Series 3 and Series 4:
- Built-in rechargeable lithium-ion battery with 18 hour battery life
- GPS, GLONASS, GALILEO and GZSS
- LTE and UMTS on GPS + Mobile Models
- 802.11b / g / n 2.4GHz Wi-Fi
- Barometric altimeter  Water resistance up to 50 meters
- Optical heart rate sensor
- Ambient light sensor
- Power sensor
- Display with 1000 nits brightness
- Magnetic charger cable and USB power adapter included
If you are interested, Apple Watch Series 4 pre-orders kick at 12:01 PDT on September 14th. Our pre-order feature can help you determine when pre-orders go up for you if you are in another time zone. We also went along with Apple Watch Series 4 after yesterday's "Gather Round" event, which you can read here.