Checking Whether LazyDFU Is Actually Speeding Up Your Game

Measure Before and After

To know if LazyDFU helps, time your startup with and without it. Remove the jar from your mods folder, launch the game, and note how long the black screen lasts before the main menu appears. Then put the jar back and repeat. On a slow laptop the difference can be close to a minute; on fast hardware it may be only a few seconds. Use a phone timer rather than guessing.

Where the Savings Come From

The mod skips the pre-building of world-conversion rules that vanilla finishes before the window shows. That step is heavy on both CPU and memory. If your machine is powerful, that step was already quick, so the gain is small. If your machine is weak, the gain is large. This is why the mod is described as helping weaker hardware most.

Interpreting Your Results

If you see no difference at all, check that the mod is loaded in your mod list. If it is loaded but startup is still slow, the delay is coming from something else, such as a large modpack, slow storage, or Java memory settings. LazyDFU only targets one specific startup step, so it cannot fix unrelated bottlenecks.