diff --git a/pkg/perfdata/perfdata.go b/pkg/perfdata/perfdata.go
index bc4ba52..fc1914e 100644
--- a/pkg/perfdata/perfdata.go
+++ b/pkg/perfdata/perfdata.go
@@ -3,7 +3,6 @@
 package perfdata // import nocternity.net/gomonop/pkg/perfdata
 
 import (
-	"fmt"
 	"strings"
 )
 
@@ -70,26 +69,28 @@ func (d *PerfData) String() string {
 	var strBuilder strings.Builder
 	needsQuotes := strings.ContainsAny(d.Label, " '=\"")
 	if needsQuotes {
-		strBuilder.WriteString("'")
+		strBuilder.WriteRune('\'')
 	}
 	strBuilder.WriteString(strings.ReplaceAll(d.Label, "'", "''"))
 	if needsQuotes {
-		strBuilder.WriteString("'")
+		strBuilder.WriteRune('\'')
 	}
-	strBuilder.WriteString("=")
-	strBuilder.WriteString(fmt.Sprintf("%s%s;", d.value, d.units.String()))
+	strBuilder.WriteRune('=')
+	strBuilder.WriteString(d.value)
+	strBuilder.WriteString(d.units.String())
+	strBuilder.WriteRune(';')
 	if d.bits&PDatWarn != 0 {
 		strBuilder.WriteString(d.warn.String())
 	}
-	strBuilder.WriteString(";")
+	strBuilder.WriteRune(';')
 	if d.bits&PDatCrit != 0 {
 		strBuilder.WriteString(d.crit.String())
 	}
-	strBuilder.WriteString(";")
+	strBuilder.WriteRune(';')
 	if d.bits&PDatMin != 0 {
 		strBuilder.WriteString(d.min)
 	}
-	strBuilder.WriteString(";")
+	strBuilder.WriteRune(';')
 	if d.bits&PDatMax != 0 {
 		strBuilder.WriteString(d.max)
 	}