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by coryrc 66 days ago
Every single hardware subsystem adds lag. Double buffering adds a frame of lag; some do triple-buffering. USB adds ~8ms worse-case. LCD TVs add their own multi-frame lag-inducing processing, but even the ones that don't have to load the entire frame before any of it shows, which can be a substantial fraction of the time between frames.

Those old systems were "racing the beam", generating every pixel as it was being displayed. Minimum lag was microseconds. With LCDs you can't get under milliseconds. Luckily human visual perception isn't /that/ great so single-digit milliseconds could be as instantaneous, if you run at 100 Hz without double-buffering (is that even possible anymore!?) and use a low-latency keyboard (IIRC you can schedule more frequent USB frames at higher speeds) and only debounce on key release.
1 comments
wincy 66 days ago
8khz polling rate mouse and keyboard, 240hz 4K monitor (with Oled to reduce smearing preferably, or it becomes very noticeable), 360hz 1440p, or 480hz 1080p, is current state of the art. You need a decent processor and GPU (especially the high refresh rate monitors as you’re pushing a huge amount data to your display, as only the newest GPUs support the newest display port standard) to run all this, but my Windows desktop is a joy to use because of all of this. Everything is super snappy. Alternatively, buying an iPad Pro is another excellent way to get very low latencies out of the box.

I really love this blog post from Dan Luu about latency. https://danluu.com/input-lag/

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coryrc 66 days ago
That's a good one. I probably should have brought up variance though. These cache-less systems had none. Windows might just decide to index a bunch of stuff and trash your cache, and it runs slow for a bit while loading gigabytes of crap back into memory. When I flip my lightswitch, it's always (perceptibly) the same amount of time until the light comes on. Click a button on the screen? Uh...
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wincy 64 days ago
Hah, that’s a good point! Unfortunately I have Hue smart bulbs and while they’re extremely convenient and better than most, there is sometimes a slight pause when using my WiFi controlled color schemes to switch between my configured red and daylight modes. What you gain in convenience and accessibility (being able to say “turn off the master bedroom” when I’m tired is amazing) I’ve lost in pure speed and consistency.
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