x86 is used for a 32-bit operating system. It originated from the architecture used in the CPU of Intel 8086 microprocessor. x64 is used for a 64-bit operating system. It is used by many leading companies like Intel, VIA, Apple etc
x86 follows a 32 bit instruction set. x64 consists of a 64 bit instruction set.
x86 means that 32bit and 64bit computers can run it. x64 means that 64bit computers alone can run it.
x86 is the architectural interface used by Intel. X64 is the architectural interface used by AMD.
x86 refers to the Intel processor architecture that was used in PCs. Model numbers were 8088, 8086, 286, 386, 486. x64 is the architecture name for the extensions to the x86 instruction set that enable 64-bit code.
Also called by x86_64 and AMD64..
X86 means Intel 80×86 compatible. This is used to include the 8086, a 16-bit only processor. Nowadays it roughly means any CPU with a 32-bit Intel compatible instruction set X64 means a CPU that is x86 compatible but has a 64-bit mode as well
In case of a x86, a computer can only access two processor cores, For this reason the dual core processor came into being. x64 allows the computer to access up to either 8 or 12 cores currently, which lets the machine run at a much greater speed.
In X86 machine the maximum capacity of RAM is 4GB. But now-a-days will the emergence of various technologies and apps, the memory capacity of 4GB is not enough. It might be suitable for basic tasks but for running multiple tasks at a time, the memory needs an upgrade.. Moreover a 4GB RAM has about 3.2 GB for use The amount that a RAM can address in X64  is 8TB, which is a massive one. The server machines using X64 can have a RAM of limit 128TB. So to run multiple tasks X64 is the best one to choose.
X86 applications are compatible on both x86 and x64 systems. Thus if compatibility is taken into consideration, X86 is more flexible Compiling for x64, might give an advantage in speed but limits the application to only run on 64bit Operating Systems.
A 32-bit computer cannot run 64-bit Windows or 64-bit programs. Since the instruction set is different and does not support x86 version 64-bit systems can run 32-bit programs, as they’re backward compatible. This is one of the most noticeable feature as there can be a migration of applications from x86 version to x64 version, in that case backward compatibility is the most helpful
Utility wise, x86 provides programs with quite few resources to work with. Utility wise, x64 provides programs with a lot more resources to work with (there are twice as many general purpose registers and twice as many SIMD registers).
It is a lot less flexible and less secure in comparison to x64. It’s a lot more secure. No-Execute bit and data execution prevention support is mandatory.
It’s much more flexible. Periodic routines that were previously performed or supported in hardware such as task switching are shifted entirely to software.
The data in x86 machine moves in 32 bit chunks. Thus it is less efficient In x64 machine the data moves in 64 bit chunks so the efficiency in this is far better
Not only RAM, one of the drawbacks of x86 machine is that is also supports less amount of virtual memory In X64 machine the amount of virtual memory is larger than its predecessors and thus it is becoming more popular in large companies where there is a need of faster machines to run large applications at a time