The first Pentium processor’s spec sheet looked like this

Core Frequency: 75 MHz
Board Frequency: 50 MHz
Clock Multiplier: 1.5
Data bus (ext.): 64 Bit
Address bus: 32 Bit
Transistors: 3,300,000
Circuit Size: 0.60 µ
Voltage: 3.3 V

The Pentium series was largely fabricated on the then cutting edge 350nm technology, silicon fabrication technology has come a long way since then, the latest Core 2 Duo line of Intel Microprocessors are fabricated on the 65nm process and have more than 150 times the number of transistors than the first Pentium chip. Intel has produced the first ever fully functional SRAM chip based on the 45nm process technology, and is on track to start large scale manufacture by 2nd half of 2007.
Increasing transistor density and decreasing the amount of power used are the two greatest challenges which drive Silicon technology today , 45nm chips will have a greater performance/Watt advantage and will enable engineers to squeeze in twice the number of transistors in the same given area, this will enable smaller chip sizes and more number of transistors per chip which are very important for mobile devices . The new technology also promises a significant increase in transistor switching speeds and decreased transistor leakage which will eventually lead to smaller low power – high performance devices. TI has also made remarkable progress on this front and they plan to use their 45nm process to make memory chips, while we’ll have to wait a little longer before AMD announces their 45nm process .