diff --git a/Cargo.lock b/Cargo.lock
index 148cbfacc..6e5cc968d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -65,6 +65,11 @@ name = "elapsed"
 version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "fnv"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "fst"
 version = "0.3.0"
@@ -219,6 +224,7 @@ name = "raptor"
 version = "0.1.0"
 dependencies = [
  "byteorder 1.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "fst 0.3.0 (git+https://github.com/Kerollmops/fst.git?branch=always-match-clone)",
  "group-by 0.1.0 (git+https://github.com/Kerollmops/group-by.git)",
  "levenshtein_automata 0.1.1 (git+https://github.com/Kerollmops/levenshtein-automata.git?branch=custom-fst)",
@@ -364,6 +370,7 @@ dependencies = [
 "checksum cmake 0.1.33 (registry+https://github.com/rust-lang/crates.io-index)" = "704fbf3bb5149daab0afb255dbea24a1f08d2f4099cedb9baab6d470d4c5eefb"
 "checksum crc 1.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "d663548de7f5cca343f1e0a48d14dcfb0e9eb4e079ec58883b7251539fa10aeb"
 "checksum elapsed 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6f4e5af126dafd0741c2ad62d47f68b28602550102e5f0dd45c8a97fc8b49c29"
+"checksum fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)" = "2fad85553e09a6f881f739c29f0b00b0f01357c743266d478b68951ce23285f3"
 "checksum fst 0.3.0 (git+https://github.com/Kerollmops/fst.git?branch=always-match-clone)" = "<none>"
 "checksum fuchsia-zircon 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "2e9763c69ebaae630ba35f74888db465e49e259ba1bc0eda7d06f4a067615d82"
 "checksum fuchsia-zircon-sys 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3dcaa9ae7725d12cdb85b3ad99a434db70b468c09ded17e012d86b5c1010f7a7"
diff --git a/raptor/Cargo.toml b/raptor/Cargo.toml
index 63c39c66f..006bb4a29 100644
--- a/raptor/Cargo.toml
+++ b/raptor/Cargo.toml
@@ -5,6 +5,7 @@ authors = ["Kerollmops <renault.cle@gmail.com>"]
 
 [dependencies]
 byteorder = "1.2"
+fnv = "1.0"
 
 [dependencies.fst]
 git = "https://github.com/Kerollmops/fst.git"
diff --git a/raptor/src/lib.rs b/raptor/src/lib.rs
index ed37b5464..39bf59f2a 100644
--- a/raptor/src/lib.rs
+++ b/raptor/src/lib.rs
@@ -1,4 +1,5 @@
 extern crate fst;
+extern crate fnv;
 extern crate group_by;
 extern crate levenshtein_automata;
 extern crate byteorder;
diff --git a/raptor/src/rank/mod.rs b/raptor/src/rank/mod.rs
index 0d2a250c1..9faf3cc27 100644
--- a/raptor/src/rank/mod.rs
+++ b/raptor/src/rank/mod.rs
@@ -6,9 +6,9 @@ mod sum_of_words_position;
 mod exact;
 
 use std::cmp::Ordering;
-use std::collections::HashMap;
 use std::{mem, vec};
 use fst;
+use fnv::FnvHashMap;
 use levenshtein::Levenshtein;
 use metadata::{DocIndexes, OpWithStateBuilder, UnionWithState};
 use {Match, DocumentId};
@@ -59,7 +59,7 @@ impl Pool {
     }
 
     // TODO remove the matches HashMap, not proud of it
-    pub fn extend(&mut self, matches: &mut HashMap<DocumentId, Vec<Match>>) {
+    pub fn extend(&mut self, matches: &mut FnvHashMap<DocumentId, Vec<Match>>) {
         for doc in self.documents.iter_mut() {
             if let Some(matches) = matches.remove(&doc.document_id) {
                 doc.matches.extend(matches);
@@ -149,7 +149,7 @@ impl<'m, 'v, 'a> fst::Streamer<'a> for RankedStream<'m, 'v> {
     type Item = Document;
 
     fn next(&'a mut self) -> Option<Self::Item> {
-        let mut matches = HashMap::new();
+        let mut matches = FnvHashMap::default();
 
         loop {
             // TODO remove that when NLL are here !