The Pentium III was introduced some time after the Desktop Pentium III to the mobile market with the MMC-2.

Not only had the CPU core changed, but also the front side bus - from 66 MHz to 100 MHz. With that front side bus change, the upgrade path was partially cut. The new Pentium III processors used a memory clock of 100 MHz, while the connector to the Notebook Motherboard remained the same.

After the initial introduction of the first fixed clock mobile Pentium III processors, Intel added the Speedstep feature to its higher clocked mobile CPUs.

The Speedstep controller at the MMC-2 module needs also some support from the Notebook motherboard. You must check with your notebook vendor if your notebook can support that feature.