[Black101]

I was able to play mp3s on my 486 DX4-100Mhz if I remember correctly.

[jstsch]

Yes. My 486 DX2-66MHz could do 112kbit MP3s, but was struggling with 128kbit MP3s.

[jonpurdy]

These anecdotes mesh with what I remember. A friend in high school around 1999 had a Pentium 133; it could play MP3s without stuttering but it couldn’t do anything else while it did that.