what is the difference between apple watch three and four?
The one big difference between the Series 3 and the Series 4 is the chip inside. The Series 4 steps it up a notch with a 64-bit dual core processor, which is 2 x faster than the Series 3's dual-core processor. Both have a wireless chip and built-in lithium-ion rechargeable battery with up to 18 hours of battery life.