diff --git a/world/src/block/mod.rs b/world/src/block/mod.rs
index d7705dd6de..233f83d8a6 100644
--- a/world/src/block/mod.rs
+++ b/world/src/block/mod.rs
@@ -34,7 +34,7 @@ impl<'a> BlockGen<'a> {
 
     pub fn sample_column<'b>(
         column_gen: &ColumnGen<'a>,
-        cache: &'b mut SmallCache<Option<ColumnSample<'a>>>,
+        cache: &'b mut SmallCache<Vec2<i32>, Option<ColumnSample<'a>>>,
         wpos: Vec2<i32>,
         index: IndexRef<'a>,
         calendar: Option<&'a Calendar>,
diff --git a/world/src/index.rs b/world/src/index.rs
index 5fdaa6bff9..fc8fcd9497 100644
--- a/world/src/index.rs
+++ b/world/src/index.rs
@@ -9,7 +9,7 @@ use common::{
     trade::{SiteId, SitePrices},
 };
 use core::ops::Deref;
-use noise::{Fbm, Seedable, SuperSimplex};
+use noise::{Fbm, Seedable, SuperSimplex, MultiFractal};
 use std::sync::Arc;
 
 const WORLD_COLORS_MANIFEST: &str = "world.style.colors";
@@ -144,7 +144,7 @@ impl Noise {
         Self {
             cave_nz: SuperSimplex::new().set_seed(seed + 0),
             scatter_nz: SuperSimplex::new().set_seed(seed + 1),
-            cave_fbm_nz: Fbm::new().set_seed(seed + 2),
+            cave_fbm_nz: Fbm::new().set_seed(seed + 2).set_octaves(5),
         }
     }
 }
diff --git a/world/src/layer/cave.rs b/world/src/layer/cave.rs
index b35e9bd655..e0350aef41 100644
--- a/world/src/layer/cave.rs
+++ b/world/src/layer/cave.rs
@@ -3,7 +3,8 @@ use super::scatter::close;
 use crate::{
     site::SiteKind,
     util::{
-        sampler::Sampler, FastNoise2d, RandomField, RandomPerm, StructureGen2d, LOCALITY, SQUARE_4,
+        sampler::Sampler, FastNoise2d, RandomField, RandomPerm, SmallCache, StructureGen2d,
+        LOCALITY, SQUARE_4,
     },
     Canvas, CanvasInfo, ColumnSample, Land,
 };
@@ -20,7 +21,6 @@ use noise::NoiseFn;
 use rand::prelude::*;
 use std::{
     cmp::Ordering,
-    collections::HashMap,
     f64::consts::PI,
     ops::{Add, Mul, Range, Sub},
 };
@@ -453,7 +453,7 @@ pub fn apply_caves_to(canvas: &mut Canvas, rng: &mut impl Rng) {
             .max_by(|a, b| a.partial_cmp(b).unwrap_or(Ordering::Equal))
             .unwrap_or(0.0)
             .clamp(0.0, 1.0);
-        let mut structure_cache = HashMap::new();
+        let mut structure_cache = SmallCache::default();
         canvas.foreach_col(|canvas, wpos2d, col| {
             let tunnel_bounds =
                 tunnel_bounds_at_from(wpos2d, &info, &land, tunnels.iter().copied())
@@ -549,7 +549,7 @@ fn write_column<R: Rng>(
     tunnel: Tunnel,
     dimensions: (f32, f32, f32),
     giant_tree_factor: f32,
-    structure_cache: &mut HashMap<(Vec3<i32>, Vec2<i32>), Option<CaveStructure>>,
+    structure_cache: &mut SmallCache<Vec3<i32>, Option<CaveStructure>>,
     rng: &mut R,
 ) {
     let info = canvas.info();
@@ -681,9 +681,8 @@ fn write_column<R: Rng>(
 
     let mut get_structure = |wpos: Vec3<i32>, dynamic_rng: &mut R| {
         for (wpos2d, seed) in StructureGen2d::new(34537, 24, 8).get(wpos.xy()) {
-            let structure = if let Some(structure) = structure_cache
-                .entry((tunnel.a.wpos.with_z(tunnel.a.depth), wpos2d))
-                .or_insert_with(|| {
+            let structure = if let Some(structure) =
+                structure_cache.get(wpos2d.with_z(tunnel.a.depth), |_| {
                     let mut rng = RandomPerm::new(seed);
                     let (z_range, horizontal, vertical, _) =
                         tunnel.z_range_at(wpos2d.map(|e| e as f64 + 0.5), info)?;
diff --git a/world/src/util/small_cache.rs b/world/src/util/small_cache.rs
index 2246d5b932..4a850b952c 100644
--- a/world/src/util/small_cache.rs
+++ b/world/src/util/small_cache.rs
@@ -1,23 +1,22 @@
 use arr_macro::arr;
-use vek::*;
 
-fn calc_idx(v: Vec2<i32>) -> usize {
-    let mut x = v.x as u32;
-    let mut y = v.y as u32;
-    x = x.wrapping_mul(0x6eed0e9d);
-    y = y.wrapping_mul(0x2f72b421);
-    (x ^ y) as usize
+fn calc_idx(v: impl Iterator<Item = i32>) -> usize {
+    let mut r = 0;
+    for (e, h) in v.zip([0x6eed0e9d, 0x2f72b421, 0x18132f72, 0x891e2fba].into_iter()) {
+        r ^= (e as u32).wrapping_mul(h);
+    }
+    r as usize
 }
 
 // NOTE: Use 128 if TerrainChunkSize::RECT_SIZE.x = 128.
 const CACHE_LEN: usize = 32;
 
-pub struct SmallCache<V: Default> {
-    index: [Option<Vec2<i32>>; CACHE_LEN + 9],
+pub struct SmallCache<K, V: Default> {
+    index: [Option<K>; CACHE_LEN + 9],
     data: [V; CACHE_LEN + 9],
     random: u32,
 }
-impl<V: Default> Default for SmallCache<V> {
+impl<K: Copy, V: Default> Default for SmallCache<K, V> {
     fn default() -> Self {
         Self {
             index: [None; CACHE_LEN + 9],
@@ -26,9 +25,9 @@ impl<V: Default> Default for SmallCache<V> {
         }
     }
 }
-impl<V: Default> SmallCache<V> {
-    pub fn get<F: FnOnce(Vec2<i32>) -> V>(&mut self, key: Vec2<i32>, f: F) -> &V {
-        let idx = calc_idx(key) % CACHE_LEN;
+impl<K: Copy + Eq + IntoIterator<Item = i32>, V: Default> SmallCache<K, V> {
+    pub fn get<F: FnOnce(K) -> V>(&mut self, key: K, f: F) -> &V {
+        let idx = calc_idx(key.into_iter()) % CACHE_LEN;
 
         // Search
         if self.index[idx].as_ref().map(|k| k == &key).unwrap_or(false) {