100ms of latency = 1% in sales

Last week at the Wired conference, a speaker pointed out this fact from 2008, probably even more relevant today than ever:

Amazon found every 100ms of latency cost them 1% in sales. Google found an extra .5 seconds in search page generation time dropped traffic by 20%.

Link

I you test with users, they probably won’t notice 100ms differences. But overall it changes behaviors. At this level impatience becomes almost unconscious.