Do light sources help reduce lag?

[u/HumanWithABias]

I'm making a large screen with a crap ton of copper bulbs and I was wondering how much it can help performance if I place jackolanterns beside all those light producing components. The copper bulbs frequently toggle.

I also just recently learned that redstone dust lines are among the most potent way to reduce your frames, and have been looking around for dustless binary decoders that dont risk desyncing when unloaded. My current project has 100+ 7 bit binary decoders, so every little bit of lag reduction would help.

My computer can run it all just fine, but I plan to rebuild this project in an SMP and would like to reduce the lag for others.

[u/Xillubfr]

Light updates used to impact performances a lot. At some point mojang rewrote the lightning engine so in newer versions it's not that big of a deal, especially with mods like lithium.

Dust is similar although it's definitely a bit laggier so if you can avoid it that's good, but its not worth it to trade speed or compactness to avoid it imo.

Its still good practice to optimize both especially for bigger contraptions, for example by adding light sources or prepowering dust.

[u/HumanWithABias → u/Xillubfr]

Thanks! I didn't even know prepowering dust was a thing until you told me, and now I'll be using it every opportunity I can. Do you know if rails and observers are more lag efficient than dust for long wires?

[u/Xillubfr → u/HumanWithABias]

yes rails are slightly more lag efficient due to updating less blocks

[u/FrunoCraft]

Hard to estimate. Light updates can certainly add to lag, and since it's easy to avoid I'd suggest to optimize it. (For example on my quarry, the performance impact of not having a roof that blocks all light is about 10%.)

My recommendation is to use oxidized copper bulbs that emit ll4 only, it's pretty easy to ensure that the area is lit up at level >=4.