Pentium Processors that were of the MMX ilk, in deference to the MMX extended instruction set. A loose and unofficial term used to differentiate then from the older sans-MMX and single volatage Pentia and the later Pentium II line.

This is how the Pentium MMX falls into the scheme of things:

• Original Pentium: 60-66mHz, socket 4, single voltage
  
  
• Pentium: 75-200Mhz, socket5/socket 7, single voltage
  
  
• Pentium MMX: 150-233mHz (120-266mHz for mobile), socket 7, split vio/vcore voltages
  
  
• Pentium II: 233-450mHz, Slot 1 SECC, split voltage