The history of computer cooling has come a long way. 20 years ago CPU's didn't need much cooling to run, but as they got more powerful they produced more heat and got smaller processors.

In 1985 5 Watts per centimeter squared was considered the limits of air cooling.

In 2000 35 Watts per centimeter squared is attained by air cooling thru flow management and high performance heat sinks.(Advanced cooling Concepts and their challenges)

Here is a picture of one of the first pentium's, Cooling was just starting to become an issue. The heat problems made it so the processor was sold with a cooler glued to it. This processor is the intel overdrive processor made in 1989. Above image from the article "Toms hardware guide The mother of all CPU charts"

cooling has just become more of an importance as computers got faster. Cooling even 10 years ago was not as much importance as is it today. . The current Intel Pentium 570 (with 3.8 GHz), also known as the mini heating and power station needs as much energy at full capacity as nine Intel Pentium 100 CPUs! (Toms hardware guide The mother of all CPU charts )