Q. I'm downloading some software and it has an i586 version. What's i586?

A. Normally, you see two types of downloads available for Windows platforms: x86 for 32-bit platform and x64 (or AMD64 or x86-64) for 64-bit.

The x in x86 means any member of the x86 family, such as 286 (16-bit), 386 (32-bit), 486, and so on, all of which were based on the Intel 8086 architecture. This list includes the 586.

It was very common many years ago to hear about computers with 386 or 486 processors, but you rarely heard of 586, because the Intel 586 was actually named the Pentium (Pent for 5). The Pentium MMX processors are also 586s. The Pentium Pro, Pentium 2/3, AMD K6-2/3 are all i686, while the Pentium 4 is i786. Today's Intel i7 and AMD Phenom are the 10th generation.

If you see a version that's labeled 586, it simply means that it's built for Pentium processors or above (which really shouldn't be a problem for most of your computers).

Related Reading:

Check out hundreds more useful Q&As like this in John Savill's FAQ for Windows. Also, watch instructional videos made by John at ITTV.net.