x86-64 (also called x64, AMD64, or Intel 64) is the 64-bit extension of the x86 architecture. Originally developed by AMD and later adopted by Intel, it's now the standard architecture for desktop computers, laptops, and servers. x86-64 maintains backward compatibility with 32-bit x86 software while enabling access to vastly more RAM and improved performance for modern applications.
Why it matters
Virtually every modern PC runs on x86-64. When you download software and see options labeled "x64," "amd64," or "64-bit," you're getting the x86-64 version. Understanding this helps you choose the right software versions and explains why your computer can run both old 32-bit programs and new 64-bit applications. The lesson CPU Architectures: x86, ARM, and RISC explains how x86-64 fits into the broader landscape of processor architectures.
Key improvements over x86
The jump from 32-bit to 64-bit brings significant benefits. x86-64 can address up to 16 exabytes of RAM theoretically (practical limits are lower but still far beyond 32-bit's 4 GB cap). It also provides more CPU registers—temporary storage locations inside the processor—which helps programs run faster. Modern operating systems like Windows 10/11, macOS, and Linux are all designed primarily for x86-64.
Compatibility and naming
You'll see this architecture called by different names: "x86-64" (technical), "x64" (Microsoft's term), "amd64" (common in Linux, reflecting AMD's origin), or "Intel 64" (Intel's branding). They all refer to the same thing. x86-64 processors can run 32-bit x86 software through a compatibility mode, which is why older applications still work on modern systems.
See more
- x86
- ARM
- CISC
- CPU
- RAM
- Byte
- CPU Architectures: x86, ARM, and RISC
- What Is a CPU?
- What Is RAM?
- Why Some Computers Feel Faster