Intel Pentium II 400
An early version of the Pentium II 400: A0-stepping, 34th week of 1998 and most notable is the older style SECC1-packaging. My other Pentium II 400 came in the SECC2-packaging that is far more common.
This particular CPU came out of a Compaq system. A high-end system in it's day as the Pentium II 400 was released on April, 15th 1998. This CPU was manufactured just 4 months after release.