diff --git a/src/ffi/static_data/learnable_moves.rs b/src/ffi/static_data/learnable_moves.rs
index a1dab7b..881bf7b 100644
--- a/src/ffi/static_data/learnable_moves.rs
+++ b/src/ffi/static_data/learnable_moves.rs
@@ -6,8 +6,8 @@ use std::ptr::drop_in_place;
 
 /// Instantiates a new Learnable Moves.
 #[no_mangle]
-extern "C" fn learnable_moves_new() -> OwnedPtr<Box<dyn LearnableMoves>> {
-    Box::into_raw(Box::new(Box::new(LearnableMovesImpl::new())))
+extern "C" fn learnable_moves_new(max_level: LevelInt) -> OwnedPtr<Box<dyn LearnableMoves>> {
+    Box::into_raw(Box::new(Box::new(LearnableMovesImpl::new(max_level))))
 }
 
 /// drops a learnablemoves struct.
diff --git a/src/static_data/species_data/learnable_moves.rs b/src/static_data/species_data/learnable_moves.rs
index 0d92ff0..b4ee6c0 100755
--- a/src/static_data/species_data/learnable_moves.rs
+++ b/src/static_data/species_data/learnable_moves.rs
@@ -1,5 +1,4 @@
-use hashbrown::hash_map::Entry::{Occupied, Vacant};
-use hashbrown::HashMap;
+use indexmap::IndexSet;
 use std::fmt::Debug;
 
 use crate::defines::LevelInt;
@@ -12,48 +11,42 @@ pub trait LearnableMoves: Debug {
     /// Gets all moves a Pokemon can learn when leveling up to a specific level.
     fn get_learned_by_level(&self, level: LevelInt) -> Option<&Vec<StringKey>>;
     /// Gets the distinct moves a Pokemon can learn through leveling up.
-    fn get_distinct_level_moves(&self) -> &Vec<StringKey>;
+    fn get_distinct_level_moves(&self) -> &IndexSet<StringKey>;
 }
 
 /// The storage of the moves a Pokemon can learn.
-#[derive(Default, PartialEq, Eq, Debug)]
+#[derive(PartialEq, Eq, Debug)]
 pub struct LearnableMovesImpl {
     /// A map of the moves a Pokemon can learn per level.
-    learned_by_level: HashMap<LevelInt, Vec<StringKey>>,
+    learned_by_level: Vec<Vec<StringKey>>,
     /// A list of the distinct moves a Pokemon can learn through leveling up.
-    distinct_level_moves: Vec<StringKey>,
+    distinct_level_moves: IndexSet<StringKey>,
 }
 
 impl LearnableMovesImpl {
     /// Instantiates a new Learnable Moves.
-    pub fn new() -> Self {
-        Self::default()
+    pub fn new(max_level: LevelInt) -> Self {
+        Self {
+            learned_by_level: vec![Vec::new(); (max_level + 1) as usize],
+            distinct_level_moves: Default::default(),
+        }
     }
 }
 
 impl LearnableMoves for LearnableMovesImpl {
     /// Adds a new level move the Pokemon can learn.
     fn add_level_move(&mut self, level: LevelInt, m: &StringKey) {
-        match self.learned_by_level.entry(level) {
-            Occupied(x) => {
-                x.into_mut().push(m.clone());
-            }
-            Vacant(_) => {
-                self.learned_by_level.insert(level, vec![m.clone()]);
-            }
-        }
-        if !self.distinct_level_moves.contains(m) {
-            self.distinct_level_moves.push(m.clone());
-        }
+        self.learned_by_level.get_mut(level as usize).unwrap().push(m.clone());
+        self.distinct_level_moves.insert(m.clone());
     }
 
     /// Gets all moves a Pokemon can learn when leveling up to a specific level.
     fn get_learned_by_level(&self, level: LevelInt) -> Option<&Vec<StringKey>> {
-        self.learned_by_level.get(&level)
+        self.learned_by_level.get(level as usize)
     }
 
     /// Gets the distinct moves a Pokemon can learn through leveling up.
-    fn get_distinct_level_moves(&self) -> &Vec<StringKey> {
+    fn get_distinct_level_moves(&self) -> &IndexSet<StringKey> {
         &self.distinct_level_moves
     }
 }
@@ -64,7 +57,7 @@ pub(crate) mod tests {
 
     #[test]
     fn adds_level_moves() {
-        let mut moves = LearnableMovesImpl::new();
+        let mut moves = LearnableMovesImpl::new(100);
         moves.add_level_move(1, &"foo".into());
         moves.add_level_move(1, &"bar".into());
 
@@ -76,7 +69,7 @@ pub(crate) mod tests {
 
     #[test]
     fn adds_two_same_moves_at_different_level() {
-        let mut moves = LearnableMovesImpl::new();
+        let mut moves = LearnableMovesImpl::new(100);
 
         moves.add_level_move(1, &"foo".into());
         moves.add_level_move(5, &"foo".into());
diff --git a/src/utils/string_key.rs b/src/utils/string_key.rs
index 4c3dd5d..d4d5820 100755
--- a/src/utils/string_key.rs
+++ b/src/utils/string_key.rs
@@ -14,7 +14,6 @@ use std::sync::LazyLock;
 /// free speed out of it. Note that StringKeys also compare case insensitive, so that for example
 /// `charmander` == `Charmander`.
 #[derive(Clone, Debug)]
-
 pub struct StringKey {
     /// The underlying reference counted string.
     str: ArcStr,
@@ -29,12 +28,14 @@ static STRING_CACHE: LazyLock<RwLock<HashMap<u32, ArcStr>>> = LazyLock::new(|| R
 static EMPTY: LazyLock<StringKey> = LazyLock::new(|| StringKey::new(""));
 
 impl StringKey {
+    #[inline(always)]
     /// Gets the hash of a string.
     pub const fn get_hash(s: &str) -> u32 {
         let mut crc: u32 = 0xffffffff;
         let mut i: usize = 0;
+        let bytes = s.as_bytes();
         while i < s.len() {
-            crc = (crc >> 8) ^ CRC_TABLE[((crc ^ (to_lower(s.as_bytes()[i]) as u32)) & 0xff) as usize];
+            crc = (crc >> 8) ^ CRC_TABLE[((crc ^ (to_lower(bytes[i]) as u32)) & 0xff) as usize];
             i += 1;
         }
         crc ^ 0xffffffff
@@ -132,6 +133,7 @@ impl ValueIdentifiable for StringKey {
 /// The difference in ascii characters to translate from uppercase to lowercase.
 const CAPITAL_DIFF: u8 = b'a' - b'A';
 
+#[inline(always)]
 /// Converts a character to lowercased in a const safe way.
 const fn to_lower(c: u8) -> u8 {
     if c >= b'A' && c <= b'Z' {
diff --git a/tests/common/library_loader.rs b/tests/common/library_loader.rs
index c207aac..f209c02 100755
--- a/tests/common/library_loader.rs
+++ b/tests/common/library_loader.rs
@@ -450,7 +450,7 @@ where
 }
 
 fn parse_moves(value: &Value, move_library: &Box<dyn MoveLibrary>) -> Box<dyn LearnableMoves> {
-    let mut moves = LearnableMovesImpl::default();
+    let mut moves = LearnableMovesImpl::new(100);
 
     let level_moves = value.get("levelMoves").unwrap().as_array().unwrap();
     for level_move in level_moves {