Based on the information provided, here are the key points regarding the comparison between Qualcomm's Snapdragon X Elite and Apple's M3 processors:
The major reason for the decrease in computer size is because manufacturers have been able to make integrated circuits (ICs) smaller, allowing for crucial ICs like processors to be extremely compact, yet very powerful. This is done by stuffing more MOSFET transistors inside of a given space.
Laptops have become more powerful due to improvements in the PCB design, advancements in software, and the use of lighter but sturdier materials. The PCB—the main green board inside your laptop where all the electronic components are assembled—has evolved over the years, with high-density interconnects allowing for more connectivity in a smaller, lighter space.
Software and tools have also played their part in bringing down the size of laptops. Advanced electric circuits and system simulation software programs allow manufacturers to quickly test their designs by running simulations, saving time during the development stages.
The shrinking of ports has also contributed to the slimming down of laptops. Many laptop manufacturers are doing away with ethernet ports, which are relatively bulky. There has also been the evolution of USB ports, with USB type C ports being much smaller than earlier-generation USB ports.
The use of lithium-ion or lithium-polymer batteries, which are smaller, lighter, and can hold more power than earlier nickel-based batteries, has also contributed to the evolution of laptops.
However, there are some tradeoffs associated with slim and lightweight laptops. They often compromise on heat sink and other heat-dissipating capabilities, which can lead to thermal throttling.