diff --git a/pom.xml b/pom.xml
index ce094fd..dbf45a2 100644
--- a/pom.xml
+++ b/pom.xml
@@ -7,7 +7,7 @@
 
 	<groupId>org.goochjs</groupId>
 	<artifactId>goochjs-glicko2</artifactId>
-	<version>0.0.1-SNAPSHOT</version>
+	<version>0.0.2-SNAPSHOT</version>
 	<packaging>bundle</packaging>
 	<description>Glicko-2 rating system</description>
 	<name>glicko2</name>
diff --git a/src/main/java/org/goochjs/glicko2/RatingCalculator.java b/src/main/java/org/goochjs/glicko2/RatingCalculator.java
index 081ef04..1b14f09 100644
--- a/src/main/java/org/goochjs/glicko2/RatingCalculator.java
+++ b/src/main/java/org/goochjs/glicko2/RatingCalculator.java
@@ -61,8 +61,10 @@ public RatingCalculator(
 	 */
 	public void updateRatings(RatingPeriodResults results) {
 		for ( Rating player : results.getParticipants() ) {
-			if ( results.getResults(player).size() > 0 ) {
-				calculateNewRating(player, results.getResults(player));
+			List<Result> playerResults = results.getResults(player);
+
+			if ( !playerResults.isEmpty() ) {
+				calculateNewRating(player, playerResults);
 			} else {
 				// if a player does not compete during the rating period, then only Step 6 applies.
 				// the player's rating and volatility parameters remain the same but deviation increases
diff --git a/src/main/java/org/goochjs/glicko2/RatingPeriodResults.java b/src/main/java/org/goochjs/glicko2/RatingPeriodResults.java
index 3a7af75..27b958f 100644
--- a/src/main/java/org/goochjs/glicko2/RatingPeriodResults.java
+++ b/src/main/java/org/goochjs/glicko2/RatingPeriodResults.java
@@ -7,8 +7,11 @@
 package org.goochjs.glicko2;
 
 import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 
 /**
@@ -17,7 +20,7 @@
  * @author Jeremy Gooch
  */
 public class RatingPeriodResults {
-	private List<Result> results = new ArrayList<Result>();
+	private Map<Rating, List<Result>> results = new HashMap<Rating, List<Result>>();
 	private Set<Rating> participants = new HashSet<Rating>();
 
 	
@@ -44,9 +47,7 @@ public RatingPeriodResults(Set<Rating> participants) {
 	 * @param loser
 	 */
 	public void addResult(Rating winner, Rating loser) {
-		Result result = new Result(winner, loser);
-		
-		results.add(result);
+		this.addResult(new Result(winner, loser));
 	}
 	
 	
@@ -57,12 +58,31 @@ public void addResult(Rating winner, Rating loser) {
 	 * @param player2
 	 */
 	public void addDraw(Rating player1, Rating player2) {
-		Result result = new Result(player1, player2, true);
-		
-		results.add(result);
+		this.addResult(new Result(player1, player2, true));
 	}
-	
-	
+
+
+	private void addResult(Result result) {
+		List<Result> playerResults = results.get(result.getWinner());
+
+		if (playerResults == null) {
+			playerResults = new ArrayList<Result>();
+			results.put(result.getWinner(), playerResults);
+		}
+
+		playerResults.add(result);
+
+		playerResults = results.get(result.getLoser());
+
+		if (playerResults == null) {
+			playerResults = new ArrayList<Result>();
+			results.put(result.getLoser(), playerResults);
+		}
+
+		playerResults.add(result);
+	}
+
+
 	/**
 	 * Get a list of the results for a given player.
 	 * 
@@ -70,15 +90,13 @@ public void addDraw(Rating player1, Rating player2) {
 	 * @return List of results
 	 */
 	public List<Result> getResults(Rating player) {
-		List<Result> filteredResults = new ArrayList<Result>();
-		
-		for ( Result result : results ) {
-			if ( result.participated(player) ) {
-				filteredResults.add(result);
-			}
+		List<Result> playerResults = results.get(player);
+
+		if (playerResults != null) {
+			return playerResults;
 		}
-		
-		return filteredResults;
+
+		return Collections.emptyList();
 	}
 
 	
@@ -89,10 +107,7 @@ public List<Result> getResults(Rating player) {
 	 */
 	public Set<Rating> getParticipants() {
 		// Run through the results and make sure all players have been pushed into the participants set.
-		for ( Result result : results ) {
-			participants.add(result.getWinner());
-			participants.add(result.getLoser());
-		}
+		participants.addAll(results.keySet());
 
 		return participants;
 	}
diff --git a/src/test/java/org/goochjs/glicko2/TestGlicko2.java b/src/test/java/org/goochjs/glicko2/TestGlicko2.java
index 8dbe417..064a264 100644
--- a/src/test/java/org/goochjs/glicko2/TestGlicko2.java
+++ b/src/test/java/org/goochjs/glicko2/TestGlicko2.java
@@ -6,6 +6,9 @@
  */
 package org.goochjs.glicko2;
 
+import java.util.ArrayList;
+import java.util.List;
+
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
@@ -79,4 +82,31 @@ private void printResults(String text) {
 		System.out.println(player4);
 		System.out.println(player5);
 	}
+
+	@Test
+	public void scaleTest() {
+		int playerCount = 100000;
+		List<Rating> players = new ArrayList(playerCount);
+
+		results = new RatingPeriodResults();
+
+		for (int i = 0; i < playerCount; i++) {
+			Rating player = new Rating("player" + i, ratingSystem);
+			player.setRating(1000.0 + i % 1000);
+			players.add(player);
+		}
+
+		long start = System.currentTimeMillis();
+
+		for (int i = 0; i < playerCount; i++) {
+			results.addResult(players.get(i), players.get((i + 1) % playerCount));
+			results.addResult(players.get(i), players.get((i + 2) % playerCount));
+		}
+
+		ratingSystem.updateRatings(results);
+
+		long end = System.currentTimeMillis();
+
+		System.out.println("Execution time: " + (end - start));
+	}
 }