# Client performance — owner report (2026-10-18)

Plain-language summary of the Phase 2 benchmarks. Full tables and method:
[`RESULTS-proxy.md`](RESULTS-proxy.md). Player-facing advice:
[`PLAYER-TUNING.md`](PLAYER-TUNING.md). All numbers come from **one stand-in machine**
(Ryzen 9 9900X / RX 7800 XT, 1920×1080), not the fleet machines — see Caveats.

## TL;DR

- The tuned defaults we already ship beat upstream defaults in **every** test scene, and
  start the game about 6 s faster.
- This session shipped faster startup (ModernFix dynamic resources, −7.6 s) and a fix that
  keeps Create's fast renderer working with shaders on (Iris Flywheel Compat).
- Shaders stay **opt-in**. MakeUp shadowless is nearly free except on big Create builds;
  Complementary is expensive. Fresh Animations is the most expensive optional visual.
- Players should give Minecraft **5 GB** of memory — 4 GB is measurably worse, more is not faster.
- Two decisions for you: **remove Flerovium** (its win didn't hold up — I recommend yes), and
  **keep or revert the spawn tuning** (harmless, but it doesn't measurably cut mob load).

## What shipped

| Commit | Change |
|---|---|
| `7841361` | ModernFix `mixin.perf.dynamic_resources=true` (enforced `config/modernfix-mixins.properties`); added **Flerovium 1.1.2** and **Iris Flywheel Compat 2.4.0** (both client-only) |
| `c5d25fa` | Fix: `7841361`'s pack index held hashes of server-re-saved spawn configs, so the server's install failed ("Hash invalid") and it didn't start at 14:06. Re-hashed; server up 14:18. Nothing was pushed. |

The Deck tier already uses Distant Horizons' LOW quality preset — the setting that won the
DH test — so no DH change was needed. Nothing has been pushed yet.

## Measured gains

| What | Before | After |
|---|---|---|
| Tuned defaults vs upstream — vista p99 frametime | 9.33 ms | 8.23 ms |
| Tuned defaults vs upstream — mob pen 1 % low | 110 fps | 186 fps |
| Tuned defaults vs upstream — startup | 31.4 s | 25.4 s |
| ModernFix dynamic resources — startup | 33.9 s | 26.3 s (plus better frametimes) |
| Iris Flywheel Compat — Create floor with MakeUp shaders, p99 | 13.26 ms | 3.98 ms |
| Iris Flywheel Compat — same scene, average fps | 117 | 644 |

(Lower p99 = fewer stutters; higher 1 % low = smoother worst moments.)

## Shaders

- Keep them **opt-in** (the pack downloads them; nothing turns them on).
- **MakeUp – Ultra Fast, shadowless profile** is close to free on terrain and airships.
- Without help, every shaderpack turns off Create's fast renderer: the Create floor dropped
  from ~974 to ~120 fps average in every profile. **Iris Flywheel Compat**, now shipped, fixes
  that (table above). It's an unofficial mod, so it may break when Create or Iris update.
- **Complementary** is costly: about 2.7 ms worse p99 on the vista and about twice the frame
  time on the airship scene.
- Shader **shadows corrupt airships** (Iris issue #3164) — recommend shadowless profiles.

## Fresh Animations

Mob-pen p99 goes from 4.32 ms to **8.65 ms** with Fresh Animations, and **10.20 ms** with
the Extensions pack too. Keep it opt-in; Deck players shouldn't use it.

## Memory

**5 GB** is the smallest heap that performed as well as the best. 4 GB lost about 23 fps of
1 % low on the teleport tour; 6 and 8 GB were no better. Players set this in their launcher.

## Spawn tuning

Measured 4 times per config at three biome sites. Total mob counts barely changed
(jungle 129.5 → 128.0, river 208.0 → 211.5, warm ocean 145.0 → 136.0). The tuned species
are a bit rarer, as intended, and nothing really disappeared (the automated "back off"
flag came from species that only ever showed up once per run). **It's harmless, but it
doesn't measurably reduce the load.** No config was changed.

## Decisions needed from you

1. **Remove Flerovium?** Its earlier win was measured against an unusually bad baseline.
   On a fair re-test it was worse on the vista and a tie on the mob pen. **Recommended: yes.**
2. **Spawn tuning: keep or revert?** Keeping it costs nothing; reverting returns the mods'
   own spawn rates. Either is fine performance-wise.

## Caveats

- **One stand-in machine.** The fleet machines (Steam Deck, 7700K + GTX 1060, 6700K +
  1080 Ti) were unreachable, so results are relative and unconfirmed on real player
  hardware. This GPU makes some costs (airships, DH distance) look cheaper than they are
  on older cards.
- GPU clocks weren't pinned (no root access), which adds a little noise.
- A harness bug ran part of the first run on the wrong Java settings. Comparisons inside
  each test are still fair; details in `RESULTS-proxy.md`.

## Not done

- Spark CPU profile of the worst scene (B13).
- Confirmation on the fleet machines.
- The airship decay test (B5), which needs the fleet machines.

## Please report texture problems

ModernFix dynamic resources loads textures and models on demand. We skipped the
missing-texture check at your request, so if anyone sees purple/black "missing" blocks or
items in play, report the block/item name.