The *other* source of input lag
While my main focus has been measuring input lag purely as a function of the tv/display, it's interesting to note that the input device (aka gamepad) can make a difference too. More than just a couple MS, too.
teyah.net/ looked at a bunch of 3rd party fighting game controllers for the PS4/PS3 and the delta between the best and worst was a whopping 18ms. Which is to say that simultaneously push a button on the fastest input device and the slowest would result in the console detecting input 18ms later on the slowest. Happily, the standard ps4 controller was only 2ms behind the fastest, at least when only one was being used (multiple controllers caused radio interference).
Note that this doesn't tell us total lag - presumably the fastest device still gets polled every few MS. But you don't buy absolutes so knowing the relative performance is good enough!
Another person measured total lag for PS4 and other game systems with different controllers, from button press to measurable change in the component video signal (ie before display lag contributes anything). The values ranged from 45ms to 100ms. Certainly enough to swamp display lag in many cases. Side note: this is really interesting work but presented really poorly. Perhaps there's a proper write up somewhere other than the the only forum post I could find about it?
Most impressively of all this person, who built their own USB host (an arduino) that could "push" (electrically) the buttons on a device, and then measure the time to get a different controller state back over the USB cable. And, they did an excellent write up and graphical presentation of their results too. It's so nicely presented I won't bother to summarize the results other than to say again the range of lags were 2 to 23ms.
teyah.net/ looked at a bunch of 3rd party fighting game controllers for the PS4/PS3 and the delta between the best and worst was a whopping 18ms. Which is to say that simultaneously push a button on the fastest input device and the slowest would result in the console detecting input 18ms later on the slowest. Happily, the standard ps4 controller was only 2ms behind the fastest, at least when only one was being used (multiple controllers caused radio interference).
Note that this doesn't tell us total lag - presumably the fastest device still gets polled every few MS. But you don't buy absolutes so knowing the relative performance is good enough!
Another person measured total lag for PS4 and other game systems with different controllers, from button press to measurable change in the component video signal (ie before display lag contributes anything). The values ranged from 45ms to 100ms. Certainly enough to swamp display lag in many cases. Side note: this is really interesting work but presented really poorly. Perhaps there's a proper write up somewhere other than the the only forum post I could find about it?
Most impressively of all this person, who built their own USB host (an arduino) that could "push" (electrically) the buttons on a device, and then measure the time to get a different controller state back over the USB cable. And, they did an excellent write up and graphical presentation of their results too. It's so nicely presented I won't bother to summarize the results other than to say again the range of lags were 2 to 23ms.
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