Home appliances have made tremendous advances in the last 50 years in terms of efficiency. A lot of this drive was simply to cut manufacturing costs. Refrigerators in particular have made considerable advances almost every decade.

In the last 30 years the regulations around water consumption have driven rapid development in dish and clothes washer technology which has also improved their electrical efficiency.

The efficiencies we see today in desktop and server CPUs were less intentional and more a bi-product of the performance goals. Modern Intel CPUs have their origins in the Centrino mobile platform of the early 2000s, a variant of the P3. The Netburst CPUs of the time eschewed efficiency for speed and so P4 chips were very hot and inefficient, when Intel hit a ceiling with TDP and clockspeeds they had to reevaluate the situation. With Centrino, Intel's mobile CPU, they were trying to make the most power efficient CPU they could and concluded that the faster the CPU could complete it's workload and power down, the more battery could be saved. The end result was a very powerful and power efficient CPU. Intel found that with a few tweaks Centrino could outperform Netburst at a lower clockspeed and with far less power consumption.