each bit extra is twice the capacity, i wonder when we will move towards 128 bit.

For memory, may be after 64 bit addressing is no enough...

Last time I encounter 64-bit address is not all accessible, only 40-bit address, and need some tweaks to access all 64-bit memory....  

Then when doing bootloader also I encounter A20 line, or else cannot access full width of memory address (not sure how many bits).....
That's when I start pening pening kepala, give up studying the width of bus, memory address...     

Intel® architecture powers datacenters and personal computers around the world. Since its introduction by Intel® in 1978, the architecture has continuously evolved to take advantage of emerging workloads and the relentless pace of Moore’s law. The original instruction set defined only eight 16-bit general-purpose registers, which over the years were doubled in number and quadrupled in size. A large set of vector registers was added, and most recently Intel® AMX introduced two-dimensional matrix registers, providing a big jump in AI performance.1

Today, we are introducing the next major step in the evolution of Intel® architecture. Intel® Advanced Performance Extensions (Intel® APX) expands the entire x86 instruction set with access to more registers and adds various new features that improve general-purpose performance. The extensions are designed to provide efficient performance gains across a variety of workloads – without significantly increasing silicon area or power consumption of the core.

Intel® APX doubles the number of general-purpose registers (GPRs) from 16 to 32. This allows the compiler to keep more values in registers; as a result, APX-compiled code contains 10% fewer loads and more than 20% fewer stores than the same code compiled for an Intel® 64 baseline.2 Register accesses are not only faster, but they also consume significantly less dynamic power than complex load and store operations

each bit extra is twice the capacity, i wonder when we will move towards 128 bit.

APX!

https://www.intel.com/content/www/us/en/dev...nsions-apx.html

Those Windows-based 32-bit test bench PCs in the manufacturing facility would undoubtedly suffer if their codes continue to employ 32-bit vendor device driver libraries; some are legacy driver codes that have not been changed to 64-bit.

40 bit address can handle up to 1 TB (some system is 48 bit up to 256 TB), 

40 bit address can handle up to 1 TB (some system is 48 bit up to 256 TB),