Modpacks

• Check the memory setting. The launcher default is too low for the bigger packs, and too little memory feels exactly like a slow computer. Table above.
• Laptops: plug in, and on Windows make sure Minecraft uses the real graphics card, not the built-in one: Settings → System → Display → Graphics, add Java, set it to High performance.
• With Voxy or Distant Horizons, keep normal render distance at 8–12 chunks. (Video Settings → Render Distance.) The far-view mod draws everything beyond that far more cheaply. This is also what the Complementary shader authors recommend.
• Sodium Extra adds pages to Video Settings where you can switch off particles, animations and other details one by one. Great for finding what’s eating your frames.
• Crowded farms and villages slow? On the PC packs, try switching Fresh Animations off in Options → Resource Packs. Animated mobs cost something, and a hundred of them cost a hundred times that.
• Close whatever else is using your graphics card. Yes, including the browser with 40 tabs.

Settings: Mod Menu → Voxy → the settings button. The ones that matter:

• Render distance (in chunks): the big one. Complementary’s authors suggest 64–256 chunks with Voxy. Drop it first.
• Pixels² of subdivision size: how early far terrain switches to a coarser version. A higher number means blockier distance and better FPS.
• Service threads: how many CPU threads Voxy uses to build far terrain. If your CPU sits at 100% and the game stutters, lower it.
• Use sodium threads: Voxy’s own description says it can reduce stutter when moving fast at high render distance. Try it if flying with elytra hitches.
• SSAO Mode: soft shadows in corners of the far terrain. Leave it on Auto unless you’re hunting for every frame.

Settings: the Distant Horizons button in Video Settings. I tuned these for Apple Silicon, so change them only if it actually runs badly. Then, in this order:

• CPU Load: how hard Distant Horizons works in the background, from Minimal Impact up to I Paid For The Whole CPU (their name, not mine). If the game stutters, step this down first.
• LOD Render Distance Radius: how far it draws. Complementary’s authors suggest 64–128 chunks with Distant Horizons.
• Quality Preset: how detailed the far terrain is. One step lower is hard to spot from a mountain top and easy to spot in your FPS counter.

Shaders are the single biggest FPS cost. Options → Video Settings → Shader Packs, then Shader Pack Settings for the selected one.

• Quickest fix: switch to MakeUp UltraFast or Sundial Lite. They’re in every pack precisely because they’re light. Or turn shaders off and enjoy the frames.
• Complementary (Reimagined or Unbound): pick a lower Profile at the top of its settings: Potato, Very Low, Low, Medium, High (the default), Very High, Ultra. That alone usually does it.
• Still slow? In Complementary’s Performance Settings, the heavy hitters are Real-Time Shadows, Shadow Distance, Light Shaft Quality, Cloud Quality, Edge Shadow (SSAO) Quality and the two reflection qualities. Lower them one at a time.
• Advanced Color Tracing colours block light by building a voxel copy of the world around you. It’s as expensive as it sounds. Off is fine.
• The PC High pack’s fanciest shaders (Alpha Piscium, IterationT, Solas) are there for screenshots and for people who own a space heater. Don’t judge the pack by them.

What it is: a PBR texture pack. Every block gets extra texture maps that tell the shader how bumpy and how shiny each pixel is, so stone looks rough, ores glint and wet surfaces reflect. It only does anything with a shader that reads labPBR. Without that, it’s just a nice 128×128 retexture.

Turning it on: the resource pack must be active (Options → Resource Packs), and the shader has to be told. In Complementary: Materials → RP Support → labPBR. The texture pack’s author also recommends POM Depth at 1.00 on the same page. The PC Mid and High packs should already have this set; on the Mac pack, check.

If it costs too much: 128×128 textures use a lot more video memory than vanilla’s 16×16, and the bumpy-surface effect (parallax) costs extra on top. Set RP Support back to Integrated PBR+ (Complementary’s own built-in version, which it recommends anyway) and switch AVPBR off in Resource Packs. You’ll get most of the look for much less.