Also commonly referred to as lag, latency is the delay between an input and a response, or it can be in the other direction of a feedback system like steering where the delay is between an event and you feeling the feedback from it.

I was never a fan of early throttle-by-wire systems a couple of decades ago because of that latency.

When you press the pedal with throttle-by-wire, you're not opening the throttle valve you're instead making a torque (engine output) request, and that has to go through a small digital committee who decide a moment later that for your request to be fulfilled the throttle needs to be opened (and some other changes may need to be made as well, such as to the cam timing, the ignition timing, the fuel delivery and so on).

Thankfully that delay was reduced to unnoticeable in subsequent models a long time ago, but early throttle-by-wire cars also served as a lesson that latency is not something you want in any control system that you, the human, need to be in direct control of.

In the case of gaming, I would strongly argue that latency is actually a far more important performance feature for your hardware than the framerate (frames per second or fps). One of the tricks to improve render latency (just the time it takes to process a frame, there may be other latency elsewhere, such as in your TV or monitor as it receives and then displays that signal) is capping the framerate.

You can test and measure this yourself in many cases. There are various tools and utilities that can monitor this on PC, and Nvidia GPU users for example can use the company's GeForce Experience to activate a performance monitoring overlay that will show stats like render latency. That number will be in milliseconds (ms) and at 60fps for example (plenty for the human eye to see a smooth picture on a screen, as long as there are no frame skips), the gap from one frame to the next is 16.67ms. So, if you're getting a consistent 100fps or more but the render latency shown in that performance overlay is more like 66ms, you will be experiencing unnecessary render lag that defeats the purpose of making the GPU produce 100fps.

There's other latency too. According to Content Manager for Assetto Corsa, the latency for my gaming wheel is 33ms (just two frames at 60fps, which is pretty good).

That leads us nicely to the concept of steer-by-wire systems in cars. Steer by wire, as an invention, is also very old, but it hasn't really found its way onto roads the way that throttle-by-wire has. That's not to say they don't exist. Infinity offered it (at least as an option, called Direct Adaptive Steering, DAS) in the Q50 way back in late 2013.

The concept is now sound from a performance perspective at least, and steer-by-wire has been used in the occasional race car too. In the 2020 Nurburgring 24 Hours a Porsche Cayman GT4 ran such a system to second in class, and in the 2021 race a Mercedes-AMG GT3 used the same system without a steering-related incident.

Meanwhile, many planes have been fly-by-wire for ages, but their systems are also routinely checked (and replaced) far more often than any road car, and cars have to be reliable enough to still function safely even past the age of 20 in plenty of cases. So I guess the lesson is, the more technology progresses, the more important it becomes on used vehicles to actually check that everything is still fully-serviceable before we use (or buy) it. Or maybe the legislation around roadworthiness just needs to keep up.

Back on the topic of performance though, steer-by-wire does offer developers the possibility of modifying the feedback to the driver, and in the case of the Q50, it does have different modes and steering weights to choose from.

Vehicle developers can also modify the feedback details (bumps, understeer, oversteer and so on), which is something that, if we look at sim racing for example, seems to be very much about personal preference with each game feeling a bit different to the next.