According to the popular computer architecture textbook Computer Organization and Design by Turing Award winners John Hennessy and David Patterson:
The Pentium floating-point divide bug even made the "Top 10 List" of the David Letterman Late Show on television.
I have been unable to verify this. The bug was reported in October 1994 and remained in the news until early 1995. I could find nothing relevant in the Top Ten List Archive for late
1994 or early
1995. In early January, there was the
Top Ten Signs You Bought a Bad Computer, but it has no mention of Intel or math.
I did find a
Master's thesis that cites Jarrett in saying that "David Letterman included a  Pentium™ joke in his nightly monologue":
Jarrett, Jim. "A Postmortem on the Pentium Processor Crisis." Unpublished manuscript prepared for lnteleads, 1994.
9.9999973251 - Your old PC is too accurate.
8.9999163362 - Provides really good alibi when the IRS calls.
7.9999414610 - Attracted by Intel's new You don't need to know what's inside ad campaign.
6.9999831538 - It redefines computing -- and mathematics!
5.9999835137 - You've always wondered what it would be like to be a plaintiff.
4.9999999021 - Current paperweight not big enough.
3.9998245917 - Takes concept of floating point to a whole new level.
2.9991523619 - You always round off to the nearest hundred anyway.
1.9999103517 - Got a great deal from Jet Propulsion Laboratory!
And the number one reason to buy a Pentium:
0.9999999998 - It'll probably work!
"You know what goes great with those defective Pentium chips?
Defective Pentium salsa!" (David Letterman)
I conclude that David Letterman joked about the Pentium in a monologue (although I have only circumstantial evidence) not in a Top Ten List.
This is my first foray into computing history. Please let me know if you have additional information, if my reasoning is unsound, or if I should do anything besides notifying the authors and publisher. (I'm acquainted with David Patterson but would not cold email John Hennessy.)
Ellen Spertus
Professor of Computer Science