A recent Intel study shows that the compute load that required 184 single-core processors in 2005 now can be handled with just 21 processors, where every nine servers gets replaced by one.
For 40 years, technology rode Moore's Law to yield ever-more-powerful processors at lower cost. Its compounding effect was astounding: One of the best analogies is that we now have more processing power in a smartphone than the Apollo astronauts had when they landed on the moon. At the same time, though, the electrical power requirements for those processors continued to increase at a similar rate as the increase in transistor count. While new technologies (CMOS, for example) provided a one-time step-down in power requirements, each turn-up in processor frequency and density resulted in similar power increases.
As a result, by the 2000-2005 timeframe, the industry grew concerned about the amount of power and cooling required for each rack in the data center. And with the enormous increase in servers spurred by Internet commerce, most IT shops have labored for the past decade to supply adequate data center power and cooling.
In the meantime, most IT shops have experienced compute and storage growth rates of 20% to 50% a year, requiring either additional data centers or major increases in power and cooling capacity at existing centers. Since 2008, there has been some alleviation due to both slower business growth and the benefits of virtualization, which has let companies reduce their number of servers by as much as 10 to 1 for 30% to 70% of their footprint. But IT shops can deploy virtualization only once, suggesting that they'll be staring at a data center build or major upgrade in the next few years.
But an interesting thing has happened to server power efficiency. Before 2006, such efficiency improvements were nominal, represented by the solid blue line below. Even if your data center kept the number of servers steady but just migrated to the latest model, it would need significant increases in power and cooling. You'd experience greater compute performance, of course, but your power and cooling would increase in a corresponding fashion. Since 2006, however, compute efficiency (green line) has improved dramatically, even outpacing the improvement in processor performance (red lines).
The chart above shows how the compute efficiency (performance per watt -- green line) has shifted dramatically from its historical trend (blue line). And it's improving about as fast as compute performance is improving (red lines), perhaps even faster. The chart above is for the HP DL 380 server line over the past decade, but most servers are showing a similar shift.