Parsed from User-Agent using UAParser.js.
CPU architecture identifies the processor instruction set your device uses. Common values include x86, x64 (AMD64), ARM, and ARM64 (aarch64). This attribute:
CPU architectures represent different instruction set families that processors use. Understanding the user's architecture is essential for:
Era: 1980s-2000s dominant for PCs
Status: Legacy, rare in modern browsers
Indicates: Very old computer or specialized embedded system
Era: 2000s-present for desktops/laptops
Status: Standard for Windows/Linux PCs
Devices: Intel Core series, AMD Ryzen, older Macs (pre-2020)
Era: 2000s-2010s for mobile devices
Status: Being phased out, replaced by ARM64
Devices: Older Android phones, Raspberry Pi
Era: 2013-present
Status: Dominant in mobile, growing in desktops
Devices: All modern smartphones, Apple Silicon Macs (M1/M2/M3), newer Chromebooks
| Value | Meaning | Common Devices |
|---|---|---|
| amd64 / x64 | 64-bit Intel/AMD | Windows PCs, Intel Macs, most Linux desktops |
| arm64 / aarch64 | 64-bit ARM | iPhones, Android phones, M1/M2/M3 Macs, tablets |
| arm / armv7 | 32-bit ARM | Older Android phones, Raspberry Pi, legacy devices |
| x86 / ia32 | 32-bit Intel | Very old computers, rare in modern browsers |
| Unknown | Not detected | Some browsers hide architecture for privacy |
Since 2020, new Macs use Apple's ARM-based M-series chips (M1, M2, M3) instead of Intel x64 processors. If you see "arm64" + "macOS", it's an Apple Silicon Mac.
| Platform | Detection | Typical Value |
|---|---|---|
| Windows PC (Intel/AMD) | Accurate | "amd64" or "x64" in User-Agent |
| Windows PC (ARM) | Accurate | "arm64" (Surface Pro X, ARM-based PCs) |
| Mac (Intel) | Accurate | "Intel" or "x86_64" in User-Agent |
| Mac (Apple Silicon) | Accurate | "arm64" or "aarch64" |
| Linux Desktop | Accurate | "x86_64" (most common) or "aarch64" |
| Android Phones | Variable | Often omitted, sometimes "arm64" |
| iPhones/iPads | Accurate | Always ARM64 (inferred from iOS) |
CPU architecture alone is not highly identifying (billions share the same architecture), but it contributes to fingerprinting when combined with OS, browser, and device details.
arm64: Almost certainly a mobile device or Apple Silicon Mac
x64: Likely desktop/laptop Windows or Linux machine
x86 (32-bit): Very old device (10+ years), low value
arm64 + macOS: New Mac (2020+), premium device
arm64 + Windows: Rare ARM Windows device (Surface Pro X)
ARM Linux: Likely Raspberry Pi enthusiast, developer, or hobbyist
Apple Silicon Mac: Early adopter who upgraded recently
CPU architecture becomes more identifying when combined with:
Unlike device model or plugins, CPU architecture is shared by billions of users. For example:
The risk comes from combination with other attributes, not architecture alone.
CPU architecture is less critical for privacy than other attributes, but you can control it:
Effect: Changes reported architecture in User-Agent string
Limitation: Other APIs (WebAssembly feature detection) may reveal true architecture
Approach: Reports generic x64 architecture for all desktop users
Mobile: Reports generic ARM or omits architecture
Effect: Standardizes reported architecture
Enable: about:config → privacy.resistFingerprinting = true
For most users, CPU architecture is not a significant privacy risk on its own. Focus efforts on:
For daily use: Accept architecture disclosure, use tracking protection
For high privacy: Use Tor Browser (standardizes architecture)