The Worst CPUs Ever Made

Back in June, we rounded up the history of Intel’s 8086 architecture, both before and after the industry-changing Pentium Pro. For this retrospective, we’ve decided to revisit some of the worst CPUs ever built, from multiple vendors. To make it on to this list, a CPU needed to be fundamentally broken, as opposed to simply being poorly positioned or slower than expected. The annals of history are already stuffed with mediocre products that didn’t quite meet expectations but weren’t truly bad.

Plenty of people will bring up the Pentium FDIV bug here, but the reason we didn’t include it is simple: Despite being an enormous marketing failure for Intel and a huge expense, the actual bug was tiny. It impacted no one who wasn’t already doing scientific computing and the scale and scope of the problem in technical terms was never estimated to be much of anything. The incident is recalled today more for the disastrous way Intel handled it than for any overarching problem in the Pentium microarchitecture.

We also include a few dishonorable mentions. These chips may not be the worst of the worst, but they ran into serious problems or failed to address key market segments. With that, here’s our list of the worst CPUs ever made.

Now Read: Moore’s Law is Dead, Long Live Moore’s Law, Happy 40th Anniversary to the Original Intel 8086, and The Myths of Moore’s Law