diff --git a/models/points.go b/models/points.go
index b12a226329..dc4adf3bf2 100644
--- a/models/points.go
+++ b/models/points.go
@@ -1374,7 +1374,13 @@ func pointKey(measurement string, tags Tags, fields Fields, t time.Time) ([]byte
 		}
 	}
 
-	key := MakeKey([]byte(measurement), tags)
+	estimatedSize := len(measurement) + 10 // add additional buffer for escaping & spaces
+	for _, t := range tags {
+		estimatedSize += len(t.Key) + len(t.Value) + 2
+	}
+	buf := make([]byte, 0, estimatedSize)
+
+	key := AppendMakeKey(buf, []byte(measurement), tags)
 	for field := range fields {
 		sz := seriesKeySizeV1(key, []byte(field))
 		if sz > MaxKeyLength {
@@ -2443,23 +2449,26 @@ func (p *point) Reset() {
 // again later to an int64
 // NOTE2: uint is accepted, and may be 64 bits, and is for some reason accepted...
 func (p Fields) MarshalBinary() []byte {
-	var b []byte
+	sz := len(p) - 1 // separators
 	keys := make([]string, 0, len(p))
-
 	for k := range p {
 		keys = append(keys, k)
+		sz += len(k)
 	}
 
-	// Not really necessary, can probably be removed.
-	sort.Strings(keys)
+	// Only sort if we have multiple fields to sort.
+	// This length check removes an allocation incurred by the sort.
+	if len(keys) > 1 {
+		sort.Strings(keys)
+	}
 
+	b := make([]byte, 0, sz)
 	for i, k := range keys {
 		if i > 0 {
 			b = append(b, ',')
 		}
 		b = appendField(b, k, p[k])
 	}
-
 	return b
 }