diff --git a/flake.nix b/flake.nix
index e550bb5..f9dc9e3 100644
--- a/flake.nix
+++ b/flake.nix
@@ -19,7 +19,7 @@
             name = "lazuli";
             version = "0.1.7";
             src = pkgs.nix-gitignore.gitignoreSource [ "*.csv" "*.zip" "*.json" ] ./.;
-            vendorHash = "sha256-O6R8jC8Ms5gsY2FUmuL8lTGTODfMW1CsSWuWbN27zeY=";
+            vendorHash = "sha256-KnWoZ5UK8eigYw5uMSsLu4DIhzkSXmVHaE51Mr6hFmA=";
             ldflags = [
               "-X"
               "main.Version=${version}"
diff --git a/go.mod b/go.mod
index ef02765..5da1891 100644
--- a/go.mod
+++ b/go.mod
@@ -7,7 +7,6 @@ require (
 	github.com/failsafe-go/failsafe-go v0.9.5
 	github.com/urfave/cli/v3 v3.6.2
 	go.etcd.io/bbolt v1.4.3
-	golang.org/x/text v0.33.0
 )
 
 require (
@@ -26,6 +25,7 @@ require (
 	gitlab.com/yawning/tuplehash v0.0.0-20230713102510-df83abbf9a02 // indirect
 	go.yaml.in/yaml/v2 v2.4.3 // indirect
 	golang.org/x/crypto v0.47.0 // indirect
+	golang.org/x/sync v0.19.0 // indirect
 	golang.org/x/sys v0.40.0 // indirect
 	golang.org/x/time v0.14.0 // indirect
 	google.golang.org/protobuf v1.36.11 // indirect
diff --git a/sync/record.go b/sync/record.go
index 5fca73f..f7bfc66 100644
--- a/sync/record.go
+++ b/sync/record.go
@@ -7,7 +7,6 @@ import (
 	"unicode"
 
 	"github.com/bluesky-social/indigo/atproto/syntax"
-	"golang.org/x/text/unicode/norm"
 )
 
 type ExistingRecord struct {
@@ -24,29 +23,12 @@ func normalizeString(s string) string {
 	result.Grow(len(s))
 
 	for _, r := range s {
-		if unicode.Is(unicode.Mn, r) {
-			continue
-		}
-		decomposed := norm.NFKD.String(string(r))
-		if len(decomposed) > 0 {
-			result.WriteByte(decomposed[0])
-		} else {
+		if r >= 128 || unicode.IsLetter(r) || unicode.IsNumber(r) {
 			result.WriteRune(r)
 		}
 	}
 
-	s = result.String()
-	s = strings.Map(func(r rune) rune {
-		if r >= 128 {
-			return r
-		}
-		if unicode.IsLetter(r) || unicode.IsNumber(r) {
-			return r
-		}
-		return -1
-	}, s)
-
-	return s
+	return result.String()
 }
 
 type PlayRecord struct {
@@ -61,6 +43,9 @@ type PlayRecord struct {
 	RecordingMbId          string             `json:"recordingMbId,omitempty"`
 	OriginUrl              string             `json:"originUrl"`
 	MsPlayed               int                `json:"msPlayed,omitempty"`
+
+	normalizedTrack  string `json:"-"`
+	normalizedArtist string `json:"-"`
 }
 
 func (r PlayRecord) ArtistName() string {
@@ -71,11 +56,23 @@ func (r PlayRecord) ArtistName() string {
 }
 
 func (r PlayRecord) normalizeArtist() string {
-	return normalizeString(r.ArtistName())
+	if r.normalizedArtist != "" {
+		return r.normalizedArtist
+	}
+
+	r.normalizedArtist = normalizeString(r.ArtistName())
+
+	return r.normalizedArtist
 }
 
 func (r PlayRecord) normalizeTrack() string {
-	return normalizeString(r.TrackName)
+	if r.normalizedTrack != "" {
+		return r.normalizedTrack
+	}
+
+	r.normalizedTrack = normalizeString(r.TrackName)
+
+	return r.normalizedTrack
 }
 
 func (r PlayRecord) hasMBID() bool {
@@ -84,6 +81,7 @@ func (r PlayRecord) hasMBID() bool {
 			return true
 		}
 	}
+
 	return r.RecordingMbId != ""
 }
 
@@ -92,17 +90,7 @@ func (r PlayRecord) isLastFM() bool {
 }
 
 func (r PlayRecord) betterThan(other PlayRecord) bool {
-	if r.isLastFM() && !other.isLastFM() {
-		return true
-	}
-	if !r.isLastFM() && other.isLastFM() {
-		return false
-	}
-	// Both same source, prefer the one with MBID
-	if r.hasMBID() && !other.hasMBID() {
-		return true
-	}
-	return false
+	return (r.hasMBID() && !other.hasMBID()) || (r.isLastFM() && !other.isLastFM())
 }
 
 func (r PlayRecord) IsDuplicate(other PlayRecord, tolerance time.Duration) (bool, bool) {
@@ -118,10 +106,7 @@ func (r PlayRecord) sameAs(other PlayRecord, tolerance time.Duration) bool {
 	}
 
 	diff := r.PlayedTime.Sub(other.PlayedTime.Time)
-	if diff < 0 {
-		diff = -diff
-	}
-	return diff <= tolerance
+	return max(diff, -diff) <= tolerance
 }
 
 func (r PlayRecord) Time() time.Time {
diff --git a/sync/record_test.go b/sync/record_test.go
index 832ddc2..8995b6a 100644
--- a/sync/record_test.go
+++ b/sync/record_test.go
@@ -1,6 +1,7 @@
 package sync
 
 import (
+	"fmt"
 	"testing"
 	"time"
 
@@ -438,3 +439,35 @@ func TestMergeRecordsComprehensive(t *testing.T) {
 		})
 	}
 }
+
+func BenchmarkMergeRecords(b *testing.B) {
+	// Generate test data with multiple sources and items
+	numSources := 10
+	itemsPerSource := 1000
+	tolerance := 10 * time.Minute
+	baseTime := time.Date(2024, 1, 15, 10, 0, 0, 0, time.UTC)
+
+	sources := make([][]PlayRecord, numSources)
+	for i := range numSources {
+		sources[i] = make([]PlayRecord, itemsPerSource)
+		for j := range itemsPerSource {
+			sources[i][j] = PlayRecord{
+				Type:                   "app.bsky.feed.post",
+				TrackName:              fmt.Sprintf("Song %d", (i+j)%100),
+				Artists:                []PlayRecordArtist{{ArtistName: fmt.Sprintf("Artist %d", i%20)}},
+				PlayedTime:             Timestamp{Time: baseTime.Add(time.Duration(i*itemsPerSource+j) * time.Minute)},
+				SubmissionClientAgent:  DefaultClientAgent,
+				MusicServiceBaseDomain: []string{MusicServiceLastFM, MusicServiceSpotify}[i%2],
+				OriginUrl:              "https://example.com",
+				MsPlayed:               180000,
+			}
+			if (i+j)%3 == 0 {
+				sources[i][j].RecordingMbId = "mbid-123"
+			}
+		}
+	}
+
+	for b.Loop() {
+		kway.Merge(sources, tolerance)
+	}
+}