I'm guessing that a lot of you play on low end devices, and you have experienced pretty bad performance, especially in the hub or in dungeons. You also probably use some skyblock mods, which hurt your performance. I used to be unable to do phase 2 of necron because I got lower than 5 fps (all my homies hate withermancer skulls). Since then I've tried my best to optimize performance as much as possible, and learned a lot about how to do it. That being said, if you already know a lot about performance mods, this guide may not be that useful. It's more targeted towards beginners.
Mods:
The more mods you have in your mods folder, the worse your performance will be. The first thing to do is get rid of mods you don't need that much, or try to use one mod that has as many features as possible. NEU, skytils, and patcher all contain tons of features that can eliminate the need for many other mods.
However there are also mods dedicated to improving your performance. Here are some settings I recommend using for each of those. I put the most beneficial performance features in bold.
Optifine:
- In options > video settings > details
- turn off clouds, fog, smooth biomes, rain and snow, entity shadows, and swamp colors
- set trees to smart, and if your performance is really bad, set it to fast
- set translucent blocks, dropped items, and vignette to fast
- In options > video settings > animations
- Turn off as many particles as you can, and turn off all of the animated textures if you need to. Tip for left click mages, you probably wanna turn on firework particles to see your mage beam. Hopefully someone releases a mod that disables firework particles but still renders mage beam.
- In options > video settings > quality
- turn off better grass, better snow, and emissive textures
- turn off connected textures (this also solves the "tessellating block model" crash if you've ever had it)
- if you don't use a texture pack, you can turn off all of the custom textures
- make sure anisotropic filtering and antialiasing are off
- In options > video settings > performance
- turn on smooth fps. It decreases your maximum fps and increases your min fps in less performance-intensive situations, and won't affect you in performance-intensive situations
- turn on smart animations, and fast math
- turn off render regions
- I'd recommend turning off fast render (breaks a lot of things), dynamic updates, and lazy chunk loading (doesn't work on multiplayer anyway)
- set chunk updates to 1
Patcher:
- In performance > culling
- turn on entity culling and particle culling
- you'd probably want to turn on smart entity culling and check armor stand rules
- In performance > entity rendering
- turn on disable grounded arrows, disable attached arrows
- if you like using the nametag text shadow, you may want to turn on disable nametag box. This will balance out performance and also looks better imo
- turn on entity render distance toggle, start by setting it to 32 blocks. Turn down if you still need better performance, and turn it up if your performance allows it
- In performance > general
- turn on disable GL error checking
- turning off enchant glint will improve performance and looks better imo, but it's up to you since it makes it hard to differentiate between normal and enchanted items (especially annoying when collecting from minions)
- In performance
- turn on all of the rest of the features below general
- One important thing to note is that patcher replaces many mods that you may have in your mods folder, refer to this list to see which mods you can delete, and also see some better alternatives to mods you may be using (for example, OldAnimations)
HUDCaching:
- This is a mod made by moulberry (the dev of NEU), that limits your hud to 20 fps. From my experience, you barely notice it because your hud doesn't visually update that much anyway. It's very useful if you have a lot of things rendered on your screen. I don't have much on my screen, but it even helped me by a significant amount (around +30 max fps, and +15 average)
- It was actually hard to find, because it's not in any obvious location, so you can get it here in his discord (link also has more info)
Skytils:
- While this is mainly a skyblock qol mod, it has several features that can boost your fps
- In the dungeons section, there are several settings you can use to hide nametags for certain dungeon mobs, like teracottas, wither miners, and spirit animals
- In miscellaneous, you can disable wither impact explosions and midas staff gold blocks
- You can also use hide fire on entities, hide fishing hooks, hide jerry rune, hide lighting, and hide mob death particles
ModCore:
- In your settings menu, you will most likely find a ModCore button. ModCore is included in many mods, which is why it's there and you can't get rid of it. I'd recommend turning off all of its cosmetics.
EvergreenHUD:
- This isn't a performance mod, however I find it a better alternative to other mods that display simple information on your screen (fps, cps, ping, coordinates, etc.). It's clean looking, lightweight, and has a good config menu.
Potentially bad mods:
- It's been said that sbe is pretty bad for your performance, and also has compatibility issues with the latest version of optifine. If you don't have it already I'd recommend looking for free mod alternatives (mainly skytils and dsm) before getting it. If you already have it, then I wouldn't worry about it too much
- LabyMod has compatibility issues with many mods, and the performance gained from it isn't that significant
- 5Zig (and 5Zig reborn) is a mod that is extremely bloated with features that aren't that useful. If you use it for its hud overlays, refer to EvergreenHUD
- OldAnimations (by spiderfrog) has many features that are actually better in other mods (e.g. ToggleSprint). It also has cosmetics which is pretty wasteful to you performance. Again, refer to the list I have linked in the patcher section
Clients:
- A lot of people say that badlion has a good balance between skyblock features and performance. While it does have sba and solvers, the performance isn't as good as you may think. I get the slightly less fps while using forge than when I use lunar (haven't tested on badlion but it's known to have worse performance than lunar anyway). Plus I think we can all agree that badlion is straight up hideous
Texture packs:
It has been debated how high-res (like 64x) and low-res (like 16x) packs affect your fps. A video by Intel Edits showed that it doesn't make a huge difference, but on low end pcs you'll will most likely benefit by going with a lower res pack. However from my own testing, I found that there are other factors that affect fps (I'm not really sure what they are). I get significantly lower fps using snowfault than I do using nebula, despite the fact that they are both 16x. You will probably have to test out different packs that you like on your own and find one that gives acceptable performance.
One thing that's more important is using one pack. It may be convenient to use overlays, but they can significantly reduce fps.
The most important thing is to not use custom skyblock packs. It may be hard to part ways with at first (furfsky reborn is such a cute pack), but regular pvp packs honestly look really good. If you really like sb packs then I'd recommend going into the pack and deleting all the textures you don't care about, and keep more important things like armor sets and weapons.
This last thing may or may not be true, but make sure you packs are .zip files, and not folders. This makes swapping/loading packs significantly faster, and may or may not increase your in-game performance.
Other:
Don't allocate more than 4 (or maybe 5) gb of ram. More ram can actually make it harder for java to manage memory, which hurts performance. 4 gb is pretty much the max you will ever need for minecraft. Also don't allocate more than half of your system's total ram.
If I made a mistake anywhere, or if you know of any other good tricks to improve performance, then I'd like to hear in the replies. If you know of a good performance mod, make sure to check the list linked in the patcher section to make sure it's not there. I'll try to keep this post updated for a little while, and I'll also try to update it if a new major performance mod comes out
Edit: Added skytils to the mods section and listed several skyblock specific performance improvements