“Keyboard Latency”, 2017-10-16 (; backlinks; similar):
[Dan Luu continues his investigation of why computers feel so laggy and have such high latency compared to old computers (total computer latency, terminal latency, web bloat, cf. Pavel Fatin’s “Typing with pleasure” text editor analysis).
He measures 21 keyboard latencies using a logic analyzer, finding a range of 15–60ms (!), representing a waste of a large fraction of the available ~100–200ms latency budget before a user notices and is irritated (“the median keyboard today adds as much latency as the entire end-to-end pipeline as a fast machine from the 70s.”). The latency estimates are surprising, and do not correlate with advertised traits. They simply have to be measured empirically.]
We can see that, even with the limited set of keyboards tested, there can be as much as a 45ms difference in latency between keyboards. Moreover, a modern computer with one of the slower keyboards attached can’t possibly be as responsive as a quick machine from the 70s or 80s because the keyboard alone is slower than the entire response pipeline of some older computers. That establishes the fact that modern keyboards contribute to the latency bloat we’ve seen over the past forty years…Most keyboards add enough latency to make the user experience noticeably worse, and keyboards that advertise speed aren’t necessarily faster. The two gaming keyboards we measured weren’t faster than non-gaming keyboards, and the fastest keyboard measured was a minimalist keyboard from Apple that’s marketed more on design than speed.
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