diff --git a/syncapi/notifier/notifier.go b/syncapi/notifier/notifier.go
index d2b79b63f..e1fca34bd 100644
--- a/syncapi/notifier/notifier.go
+++ b/syncapi/notifier/notifier.go
@@ -509,6 +509,7 @@ func (s userIDSet) remove(str string) {
 }
 
 func (s userIDSet) values() (vals []string) {
+	vals = make([]string, 0, len(s))
 	for str := range s {
 		vals = append(vals, str)
 	}
@@ -529,6 +530,7 @@ func (s peekingDeviceSet) remove(d types.PeekingDevice) {
 }
 
 func (s peekingDeviceSet) values() (vals []types.PeekingDevice) {
+	vals = make([]types.PeekingDevice, 0, len(s))
 	for d := range s {
 		vals = append(vals, d)
 	}
diff --git a/syncapi/streams/stream_presence.go b/syncapi/streams/stream_presence.go
index a24edad59..7b4cf982e 100644
--- a/syncapi/streams/stream_presence.go
+++ b/syncapi/streams/stream_presence.go
@@ -68,10 +68,9 @@ func (p *PresenceStreamProvider) IncrementalSync(
 	// TODO: SharedUsers might get out of sync
 	sharedUsers := p.notifier.SharedUsers(req.Device.UserID)
 
-	sharedUsersMap := map[string]bool{
-		req.Device.UserID: true,
-	}
 	// convert array to a map for easier checking if a user exists
+	sharedUsersMap := make(map[string]bool, len(sharedUsers))
+	sharedUsersMap[req.Device.UserID] = true
 	for i := range sharedUsers {
 		sharedUsersMap[sharedUsers[i]] = true
 	}