Intel Pentium Pro was the first processor from the Intel Pentium II processor family. Targeted for the server and workstation market, the Pentium Pro included integrated 256KB, 512 KB or 1 MB L2 cache running at the processor speed. The L2 cache in the Pentium Pro was not located on the same die as the CPU core. The CPU was packaged in a "dual cavity" package, where one cavity contained the processor die and another contained the L2 cache. As all other members of the Pentium 2 family, the Pentium Pro was optimized to run 32-bit applications and, when running in 32-bit mode, it significantly outperformed Pentium and Pentium MMX CPUs at the same clock speed. At the same time Pentium Pro performance with 16-bit applications was poor, and often the processor was slightly slower than similarly clocked Pentium/Pentium MMX processors. Poor performance of the Pentium II core with 16-bit applications was fixed in the desktop Pentium II CPU.
The Pentium Pro processor was the only processor from the Pentium II family that didn't have MMX instructions.