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A Few Bytes About 32-bit vs. 64-bit Processing

Written by Kelson Lawrence | Mar 25, 2013 1:49:00 PM

By Tim Charlton

What’s the difference between 32-bit and 64-bit computing?

If you’re in the market for a new computer, or perhaps just a new operating system (OS), you’ve likely noticed designations such as x86, x64, 32-bit, or 64-bit. What do these designations mean, and how do they relate to your next technology purchase? Simply put, these designations indicate the amount of data that a computer system can process at any given time.

Let’s first define a bit. A bit is a single unit of electronic data that can be represented by one of two numerical values: 1 or 0. Bits are typically streamed together in long chains to represent larger pieces of data. Every piece of data that moves through your computer, be it an e-mail, spreadsheet, or video, is nothing more than a long stream of 1s and 0s.

A computer can only work as fast as it can process these streams of bits. The task of data processing falls to several computer components, most notably the random access memory (RAM), the system bus, and the central processing unit (CPU). RAM is used to temporarily store working data in a queue until the data can be passed across the system bus to the CPU. The system bus is similar to a series of roads that can be used to transport data to the various components of the computer. The CPU accepts the data previously held in RAM and performs any necessary calculations before sending the data back to the system bus, where the data can move to its next destination.

CPUs hold data received from the RAM in a container known as a register. A 32-bit CPU can hold up to 34,359,738,368 bits at a single time. However, data is typically denoted in groups of eight bits, which are known as bytes. Therefore, a 32-bit CPU can be used to process 4,294,967,296 bytes, or 4 gigabytes (GB) at any given time. The term x86 is synonymous with 32-bit computer architecture. The first 32-bit processors were based upon the instruction set of Intel's 8086 processor. Subsequent 32-bit Intel processor names also ended with the number 86. Therefore, x86 became a common way to notate 32-bit processing.

A common misconception about 64-bit architecture, often denoted by the term x64, is that it can process double the amount of data that its 32-bit cousin can process. Well, that’s true...sort of. A 64-bit processor can actually process much more than twice the data that a 32-bit processor can handle. In fact, a 64-bit processor can theoretically process up to 18,446,744,073,709,551,616 bytes, or 16 exabytes (EB) at one time. That’s a big leap from 32-bit to 64-bit processing.

Is 64-bit processing for you?

The answer to this question might not be as simple as it seems. Although 64-bit architectures can be used to handle much larger sums of data than 32-bit allows, there are other considerations. For example, if you’re looking to upgrade your computer’s OS from a 32-bit version to a 64-bit version, your computer must have 64-bit–compatible hardware installed. Most CPUs made today are 64-bit–compatible, but you should check with your system documentation to be certain of your CPU’s specifications. On the flip side, you can typically install a 32-bit OS on 64-bit hardware without any problems.

You should also consider the amount of RAM you have or are planning to have installed inside your computer. Because a 32-bit processor can handle a maximum of 4 GB of data at one time, there is no need to install more than 4 GB of RAM in a 32-bit computer. In fact, 32-bit computers will typically only recognize 4 GB of RAM even if more is installed. Although a 64-bit system can handle up to 16 EB of data at one time, current hardware limitations typically place this amount of RAM out of reach of a single consumer system. In addition, OS manufacturers, such as Microsoft, typically place limitations far below the theoretical limit on the amount of RAM that can be used in a 64-bit system. If you are planning to use 4 GB or less of RAM, you might fare best by staying with a 32-bit system. A 64-bit system can operate with 4 GB or less of RAM, but 64-bit applications are typically larger and more resource-intensive than 32-bit versions. Therefore, the use of a 64-bit architecture could actually become a hindrance in systems with 4 GB of RAM or less.

Additionally, you need to know whether or not your existing applications and peripheral devices are compatible with a 64-bit architecture. Although 64-bit systems have been around for some time, most personal computers made over the last 20 years have been 32- or even 16-bit devices. Because of this, in the past, many developers of applications and peripheral devices focused on making their products work on these platforms only. But newer applications and peripheral drivers are now more likely to support a 64-bit architecture.

To get around the issue of application compatibility, Microsoft has included a 32-bit emulator in many of its 64-bit OSs. This allows many 32-bit versions of applications to run seamlessly on a 64-bit platform. However, applications such as printer drivers cannot be used in compatibility mode. In addition, while many 32-bit applications can run on 64-bit systems, 64-bit applications are unlikely to run on 32-bit systems.

In conclusion, a 64-bit platform can be used to process larger amounts of data more quickly than a 32-bit platform can. However, unless you’re using your computer to perform tasks that require large amounts of system resources, such as video editing or computer-aided design (CAD), you’re unlikely to see a big performance increase by moving to 64-bit. In time, the decision will be made for you as OS and hardware manufacturers increasingly migrate toward 64-bit products. But for now, if you’re only using your computer to surf the Internet or create spreadsheets, a 32-bit system should be sufficient.

To learn more about the different types of processor architectures and other topics, check out Boson’s ExSim-Max for CompTIA A+ 220-801 practice exam.