32-Bit vs 64-Bit: What Is the Difference?

32-bit and 64-bit describe how much data a processor handles in one step and how large a memory address it can use. A 32-bit processor has 32-bit general-purpose registers and addresses, and a 64-bit processor has 64-bit ones.

The address width sets how much memory the system can reach. A 32-bit address can point to 2³² locations, which is about 4 GB. A 64-bit address could in theory reach 16 exabytes, though current processors implement 48 or 57 address bits, which still allows 256 TB or more. In practice, the board and chipset limit installed memory long before the processor does.

Wider registers also let a processor work on 64-bit integers in a single instruction, which speeds up encryption, compression, large file handling and databases. The 64-bit extensions also added more registers, which is why 64-bit code often runs faster even when it does not need the extra memory.

The same idea of data width turns up elsewhere: 32-bit color, 32-bit float audio and 32-bit microcontrollers all describe how many bits are handled at once, applied to pixels, audio samples and small processors.

The bit width applies at three layers, and all three must line up. A 64-bit processor can run a 32-bit or a 64-bit operating system. A 64-bit operating system can run 64-bit software and, on x86, most 32-bit software too. A 32-bit operating system cannot run 64-bit software at all, even on a 64-bit processor.

On x86, the 64-bit extension came from AMD in 2003 as AMD64, and Intel adopted it as Intel 64. It is usually written x86-64 or x64. On Arm, 64-bit arrived with the Armv8-A architecture and its AArch64 state. Our comparison of x86 and Arm for industrial and embedded systems covers how the two families differ beyond bit width.

The table sets the two side by side for the processors and operating systems used in industrial computers today.

Microcontrollers are the main place 32-bit remains the standard. Arm Cortex-M cores are 32-bit and suit sensors and I/O controllers that never need gigabytes of memory.

Industrial software often outlives the hardware it was written for. A line that runs for 20 years can still depend on code built for a 32-bit system, and the common sticking points are predictable.

Start with the drivers, not the application. If every card and peripheral has a 64-bit driver, a move to a 64-bit Windows or Linux build is usually straightforward, and the application can keep running as 32-bit until it is rebuilt.

For Windows systems, our guide to upgrading to Windows 11 IoT Enterprise covers the long-term servicing editions used in industrial PCs. Where code depends on the ISA bus or 16-bit DOS, PC/104 single board computers keep legacy stacks running while the rest of the system moves on. For new Arm designs, 64-bit Arm SBCs are the usual starting point.

Where a driver or application cannot move, a virtual machine on a 64-bit host can run the older operating system alongside the new one. This works well for software that only needs a serial port or a network connection. It suits code that drives an ISA or PCI card directly less well, because the virtual machine cannot always pass the card through with the timing the software expects. In that case, test the card and its software on the target hardware before committing a fleet.

We install and image the operating system on every industrial computer we build, and we check driver support for your I/O cards and peripherals before choosing between a 32-bit and 64-bit build.