One SSD can handle about 40,000 reads or writes a second, whereas the average hardware gives you about 180. And it runs at about one watt as opposed to 15 watts, which means you spend far less on power. “Do the math on how much you can save”. In short, you need fewer servers to do the same amount of work.
Much more:
http://www.wired.com/wiredenterprise/2012/06/flash-data-centers/
