Computer Components

Differences Between x86 and x64 CPUs

The Origins

x86: This instruction set dates back to 1978 with the Intel 8086 processor. It belongs to the CISC (Complex Instruction Set Computing) family with instructions that can perform multiple operations in a single step. It was originally a 16 bit architecture, later changed to 32 bit.

x64: This is a 64 bit extension to the x86 instruction set, pioneered by AMD (and later adopted by Intel). It significantly expands the capabilities of x86 based processors.

Key Differences

Memory Addressing

x86 Limitation: 32 bit x86 processors can only address up to 4GB of RAM. This was a major problem for memory intensive tasks.

x64 Breakthrough: x64 processors support a theoretical maximum of 16 exabytes of RAM but that’s more than we’ll likely ever need.

Practically, modern systems usually impose other limits but the point is that memory capacity is no longer a major concern.


x86: Has a limited set of general purpose registers (tiny memory slots within the CPU for holding data).

x64: Significantly expands the number of general purpose registers from 8 to 16, and makes them 64 bit wide. This allows the CPU to work with larger chunks of data and perform calculations more efficiently.

Instruction Set

x64 Backwards Compatibility: x64 CPUs can run most x86 software natively offering a smooth transition for legacy applications.

New Tricks: x64 introduces additional instructions for taking advantage of the 64 bit capabilities, including new ways of working with data and enhancing security features.

Performance Benefits of x64

Handling Larger Data Sets: x64 shines in scenarios dealing with large numbers, high resolution images, complex datasets or just having a ton of browser tabs open.

More Efficient Calculations: Certain mathematical operations are optimized for the 64 bit environment meaning there is much faster processing.

Enhanced Security Features: x64 often comes alongside hardware level security enhancements like NX bit support which works by preventing execution of certain malicious code.

Important Things

Operating System Matters: To fully use x64 features you need a 64 bit operating system (like Windows 10 64 bit or modern Linux distributions).

32 bit on x64: Most x64 operating systems can still run 32 bit software but it won’t benefit from the 64 bit advantages.

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