Have you ever had that nagging sensation that your computer was slower than it used to be? Or that your brand new laptop seemed much more sluggish than an old tower PC you once had? Dan Luu, a computer engineer who has previously worked at Google and Microsoft, had the same sensation, so he did what the rest of us would not: He decided to test a whole slew of computational devices ranging from desktops built in 1977 to computers and tablets built this year.