Pentiums require special motherboards, because they run significantly hotter than previous processors. They require a heat sink on top of the processor to absorb and ventilate the heat.
Some of the other important changes Pentium had from the 486 are:
Superscalar architecture - The Pentium has two data paths that let it complete multiple instructions per clock cycle. The architecture has two pipes called "U" and "V". Pipe "U" can execute any instruction whereas the pipe "V" handles simplest instructions.
64-bit data path - Assists in extracting double the amount of information from the memory on each fetch when compared to 32 bit data paths.
MMX instructions- This technology contains SIMD instruction set designed to use in multimedia applications.
