In the early 90's the Pentium floating point error could fit your criteria: http://www.cs.niu.edu/other/pentium.html http://www.cs.niu.edu/other/pentium.html

In the early 90's the Pentium floating point error could fit your criteria: http://www.cs.niu.edu/other/pentium.html http://www.cs.niu.edu/other/pentium.html I remember taking the chip into Digital at the time. They replaced it for me.