Do 64-bit (x86-64) applications and operating systems have any fundamental advantages over 32-bit ones?

Question

System Programming

Everyone who caught those days and was already a programmer or "advanced user" knows that the transitions from the 16-bit architecture of Windows 3.1 to the "386th enhanced mode" of Windows 3.11, then to the full 32-bit protected mode of Windows 95 and later on the Windows NT kernel brought with them significant qualitative differences at a deep system level, which made it possible to achieve increased reliability and, on some configurations, increased performance in solving the same tasks compared to previous software architectures on the same hardware. Does x86-64 have similar advantages, or is the only reason for it being addressing more RAM?

Answer 1

In short, x86-64 in Long Mode has more registers, and they are larger than in Legacy Mode. Also, in long mode, rudiments from x86 are disabled, in particular, the segmented memory model.

Answer 2

x64 processors have larger general-purpose registers (64 bits versus 32, it’s understandable, addresses must be read and stored somewhere), and as far as I remember, there are more of them, which allows the compiler to push more data into registers, due to which, in certain cases, you can get a good performance boost.

Answer 3

As already written, 1 performance increase for those who are designed for this architecture (the notebook will not become faster). The second is the maximum amount of memory available to the application and the OS (more addresses - more memory), for a 64bit OS it will be more than for a 32bit one, how much more depends on the specific OS.