Pentium MMX bug
"Pentium FO" bug

The newest bug found on the Pentium processors is the so called Pentium FO bug, discovered in November 1997. This bug can freeze up Pentium MMX and other Pentium computers, which are used in the hundreds of millions throughout the world. The Pentium Pro processors could also be affected by the bug.

There has not been much done about the bug so, so far, there are only speculations about the bug. According to Robert Collins, the bug has been known to him for a couple of months now and he believes that Intel has known about the bug too, but Intel claims that it has just learned about the bug and is off researching it.

According to Collins, the author of the Intel Secrets page, the bug is a single illegal instruction and not something that would be deliberately coded into a software program so it will not be found in commercial software or in independently developed software. However, this instruction could be maliciously inserted into a small C program and be used to bring down a company's server computers, according to Collins.

More about the bug is yet to be found.