The Raspberry Pi hardware has included a 64-bit processor since the Pi 3 launched in early 2016, but the Raspberry Pi OS (formerly known as Raspbian) has remained primarily 32-bit. The Raspberry Pi Foundation has been testing a 64-bit version of the OS since 2020, though, and today the organization announced that the 64-bit version is leaving beta and is now a fully supported OS option on all 64-bit Pi hardware. This includes the Pi 3, Pi 4, Pi Zero 2 W, and all variants thereof.
The most significant benefit of the 64-bit switch will be software compatibility, since as the Pi Foundation notes, “many closed-source applications are only available for ARM64,” and open source apps aren’t always fully optimized for the instruction set that the 32-bit Pi OS uses.
The Pi Foundation’s post also talks about the performance benefits of 64-bit ARM processors and the underlying ARMv8 instruction set while noting that these benefits “are most visible in benchmarks” at the moment. It also mentions the ability for single processes to address more than 4GB of RAM, though the Large Physical Address Extension (LPAE) feature already allows each individual process in the 32-bit Pi OS to access up to 3GB of memory.
As of this writing, there are only two versions of the 64-bit Pi OS image available: the “Lite” version, which has no pre-installed desktop environment or apps, and the version with the desktop and a bare minimum of apps pre-installed. The “desktop with recommended apps” version of the OS isn’t available in 64-bit yet, so you’ll need to install things like LibreOffice and your preferred development tools yourself. The 64-bit versions of the images are actually a bit smaller in file size than their 32-bit counterparts, presumably because they don’t need to support the full range of Pi hardware like the 32-bit images do.
The 32-bit version of the Raspberry Pi OS image isn’t going away, and it remains supported on both 32- and 64-bit Pi devices for anyone who prefers or needs it—old Pi and Pi 2 boards with 32-bit processors remain fully supported. You’ll also need to stick with the 32-bit release if you use the “legacy” version of the Raspberry Pi OS, which still uses Debian 10 (“Buster”) as its base instead of the newer Debian 11 (“Bullseye“).
All Raspberry Pi OS images can be downloaded from the Pi Foundation’s website.