Selecting the keyword for day 24 of the A2Z Challenge 2019 was a bit challenging. In computer science, we have very few terms or keywords that start with ‘X’. All of them are ‘hi-tech’. So, after a lot of research and analysis, I selected ‘x86’ and ‘x64’. In this post, I am going to talk about the A2Z of x86 and x64 architecture.

While checking the ‘System Properties’ of your computer, you must have seen x86 or x64 based processor against system type. x86 and x64 based processors are called 32-bit and 64-bit processors respectively. x86 refers to the old 32-bit architecture whereas x64 refers to the new 64-bit architecture.

A2Z of x86 and x64- Differences

• Instruction Size: A x86 system is capable of dealing with a 32-bit instruction. x64 system is capable of dealing with a 64-bit instruction. A bit is the smallest unit of storage on a computer system. A single bit can either hold: 0 or 1.
• Memory Space: x86 system can access up to 4GB memory space [2^32bits = 4.29GB]. Theoretically, an x64 system can access up to 16EB memory space [RAM].
  • 1 bit = 0 or 1.
  • 1 byte = 8 bits.
  • 1 KB = 1024 bytes.
  • 1 MB = 1024 KB.
  • 1 GB = 1024 MB.
  • 1 TB = 1024 GB.
  • 1 PB = 1024 TB.
  • 1 EB = 1024 PB.
• OS Compatibility: x86 system can run a 32-bit OS but cannot run a 64-bit OS. x64 system can run either a 32-bit or a 64-bit OS.
• Application Compatibility: 32-bit OS can run 32-bit and 16-bit applications. 64-bit OS can run both 64-bit and 32-bit applications. They can’t run any 16-bit application.

In this post, I tried to highlight the difference between x86 and x64 systems. Have a question? Feel free to ask them in the comment box.