32-bit processorThe 32-bit processor was the primary processor used in all computers until the early1990s. Intel Pentium processors and early AMD processors were 32-bit processors. The operating system and software on a computer with a 32-bit processor is also 32-bit based, in that they work with data units that are 32 bits wide. Windows 95, 98, and XP are all 32-bit operating systems that were common on computers with 32-bit processors.Note: A computer with a 32-bit processor cannot have a 64-bit version of an operating system installed. It can only have a 32-bit version of an operating system installed.64-bit processorThe 64-bit computer has been around since 1961 when IBM created the IBM 7030 Stretch supercomputer. However, it was not put into use in home computers until the early 2000s. Microsoft released a 64-bit version of Windows XP to be used on computers with a 64-bit processor. Windows Vista, Windows 7, and Windows 8 also come in 64-bit versions. Other software has been developed that is designed to run on a 64-bit computer, which are 64-bit based as well, in that they work with data units that are 64 bits wide.Note: A computer with a 64-bit processor can have a 64-bit or 32-bit version of an operating system installed. However, with a 32-bit operating system, the 64-bit processor would not run at its full capability.Note: On a computer with a 64-bit processor, you cannot run a 16-bit legacyprogram. Many 32-bit programs will work with a 64-bit processor and operating system, but some older 32-bit programs may not function properly, or at all, due to limited or no compatibility.