ModernFix in FTB Skies 2

Same as in the All the Mods 10 8.1 guide

ModernFix is an all-in-one performance mod. It improves performance, reduces memory usage and fixes many bugs, and it aims to do all that without majorly compromising the game experience. You don't craft anything with it and there's nothing to place in your world. It works quietly in the background.^[1]

The pack ships ModernFix 5.27.20 for Minecraft 1.21.1 on NeoForge. It has been in the pack since version 2.25 or earlier.^[2]

What it does

• Backports bugfixes from newer versions of Minecraft and Forge.^[1]
• Patches mods that are no longer supported on a given Minecraft version.^[1]
• Optimizes the game's launch process to speed it up and reduce random concurrency crashes.^[1]
• Adds debug tools to help work out the cause of rare crashes and freezes without a painful mod bisection.^[1]

Who it is for

Everyone who plays the pack benefits, because it is a general-purpose fix and not a gameplay feature. It is most useful if you are on a modest amount of RAM or tired of long launches.^[1]

Where it fits in progression

Unverified The sources I have don't show any quests, ATM Star path steps or in-game guidebook entries for this mod, so it doesn't appear to be part of the progression. I also can't confirm whether the pack changes any ModernFix options from their defaults.

Same as in the All the Mods 10 8.1 guide

Good news: ModernFix is a mod you install and then mostly leave alone. It's an all-in-one mod that improves performance, reduces memory usage, and fixes many bugs, without majorly compromising the game experience.^[1]

Unverified The sources here show no quests, recipes or in-jar guidebook for this mod in the pack, so there is no list of items to craft first. Anything about how the pack configures ModernFix would be set in the pack's ModernFix config, which these sources do not show.

What to know before you play

• Its tweaks include backported bugfixes, patches for mods that are no longer supported on a given Minecraft version, and launch-process optimizations that speed up startup and reduce random concurrency crashes.^[1]
• It also adds debug tools that help you work out the cause of rare crashes and freezes, so you don't have to bisect your mods by hand.^[1]
• The mod sorts its options into these categories: bugfixes (core fixes to improve game stability), performance (features that help game and launch performance), troubleshooting (features that help diagnose problems), and expert only.^[3]
• Leave the expert-only category alone unless you know what you're doing. The mod itself says not to change those options otherwise.^[3]

Options that are off by default in the mod

ModernFix can completely redesign the game's model loading system so that models load on the fly. The mod does not enable this by default because of compatibility issues.^[1]

Another example is the option that force-loads all mixins when launch finishes and then clears out Mixin's data structures to remove most of its memory footprint. The mod disables it by default for compatibility reasons.^[3]

If something breaks

If you think ModernFix is causing a problem, report it on the project's GitHub or ask in the #modernfix-discussion channel on its Discord. Mention your Minecraft version, modloader and ModernFix version, plus the other mods you have installed.^[1]

Same as in the All the Mods 10 8.1 guide

ModernFix works differently from most mods in this guide. It is described as an all-in-one mod that improves performance, reduces memory usage and fixes bugs. The sources don't describe any machines, multiblocks, power, fluids or item automation for it, so I won't invent any. What follows is how it actually works.^[1]

What ModernFix changes

ModernFix is made up of many small tweaks rather than one big system. The project page groups them into a few types: backports of bugfixes from newer Minecraft and Forge versions, patches for mods that are no longer supported on a given Minecraft version, and optimizations to the game's launch process. It also adds debug tools to help work out the cause of rare crashes and freezes without a painful mod bisection.^[1]

For scale, the project page says most Forge 1.16-1.19.2 modpacks launch roughly twice as fast with ModernFix installed. With some non-default options enabled, it can let large modpacks run on 3GB or less of allocated memory.^[1]

Option categories

ModernFix's options are sorted into categories, and each one tells you how careful to be with it:^[3]

• Bugfixes: core fixes to improve game stability.^[3]
• Performance: features that help improve game and launch performance.^[3]
• Troubleshooting: features meant to help you diagnose problems.^[3]
• Expert only: do not change these unless you know what you are doing.^[3]

Two options worth knowing

The background JEI loading option (mixin.perf.async_jei) is described as a key optimization. It patches JEI to reload on a background thread, which removes the long delay JEI adds to world loading. The description says it is for 1.16 only, so don't assume it does anything on other Minecraft versions.^[3]

The mixin.perf.clear_mixin_classinfo option force-loads all mixins when launch finishes. It then clears out Mixin's data structures to remove most of Mixin's memory footprint. It is disabled by default for compatibility reasons.^[3]

Dynamic model loading

ModernFix can also replace the game's model loading system with a dynamic version that loads models on the fly. It is not enabled by default because of compatibility issues. The project page says it alleviates nearly all the downsides of model loading, bringing memory usage and loading times closer to how they were in 1.7.10.^[1]

Unverified The sources here show no config files for ModernFix in the pack, so I can't confirm which options are on or off. That includes whether dynamic model loading or the background JEI option applies in this pack and version. This site does hold FTB Skies 2's own recipes, read from the pack itself: look the item up in the item browser.

Same as in the All the Mods - Gravitas 4.0 guide

ModernFix has a lot of tweaks, but the only config value I can confirm for this pack is one entry in the common config file. Here is what it does and how the pack sets it.^[1][4]

Async JEI plugin blacklist

The option blacklist_async_jei_plugins is a list of JEI plugins that get loaded on the main thread instead of being loaded asynchronously. This pack sets it to a single entry: jepb:jei_plugin.^[4]

In practice, that one plugin is forced to load on the main thread while the other JEI plugins are not covered by this list.^[4]

Unverified The sources don't say what the mod's default value for this option is, so I can't tell you whether the pack changed it. They also don't explain why this plugin was listed, so treat the reason as unknown.

Unverified No other ModernFix options from the pack's config were available to me, so I can't say how the pack sets anything else, such as memory-saving or launch-speed options.

FTB Skies 2 1.22.0 ships ModernFix 5.27.24 for Minecraft 1.21.1, using the NeoForge build. The mod was already in the pack by version 1.0.1 or earlier, so it has been along for the whole ride.^[5]

The recent releases (5.26.1, and 5.27.4 through 5.27.24) don't list individual changes. Their changelogs only send you to the mod's own wiki changelog for major changes, so I won't guess at what changed in them.^{[6][7][8][9][10][11][12][13]}

Releases with detailed notes

These older releases have itemised changelogs. They describe the mod's own changes, and the sources don't say whether the pack changes any of these values.^{[14][15][16][17][18]}

• 5.25.1: removed dynamic_sounds.^[14]
• 5.24.3: three small internal tweaks. The JEI dependency no longer specifies an ordering, prototype maps are compared using value equality, and the deduplicator's hash function now also uses identity for hashing.^[15]
• 5.24.1: a hotfix that disabled ingredient_item_deduplication by default. The same release also changed ingredient item value deduplication to use reference equality of components.^[16]
• 5.24.0: added ingredient item value ItemStack deduplication, and implemented a Java 17-compatible DFU cache blaster. Construction of the recipe book search tree is now deferred. Smart ingredient sync is disabled when CraftTweaker is installed, its channel isn't registered if the option is off, and some incorrect kick logic was fixed.^[17]
• 5.23.1: removed nbt_memory_usage and disabled mixin.perf.faster_ingredients when VMP is installed. It added world join profiling plus extra system properties, including one that allows the async profiler for launch profiling. It also handles mods inserting null entries into LRUMap and invalidates memoization for non-category creative tabs when categories are rebuilt.^[18]