diff --git a/common_test.go b/common_test.go
index f46b6a8d..706a3b87 100644
--- a/common_test.go
+++ b/common_test.go
@@ -31,7 +31,7 @@ func (t *TestModel) Index(deviceID DeviceID, folder string, files []FileInfo, fl
 func (t *TestModel) IndexUpdate(deviceID DeviceID, folder string, files []FileInfo, flags uint32, options []Option) {
 }
 
-func (t *TestModel) Request(deviceID DeviceID, folder, name string, offset int64, size int, hash []byte, flags uint32, options []Option) ([]byte, error) {
+func (t *TestModel) Request(deviceID DeviceID, folder, name string, offset int64, size int, hash []byte, flags uint32, options []Option, buf []byte) error {
 	t.folder = folder
 	t.name = name
 	t.offset = offset
@@ -39,7 +39,8 @@ func (t *TestModel) Request(deviceID DeviceID, folder, name string, offset int64
 	t.hash = hash
 	t.flags = flags
 	t.options = options
-	return t.data, nil
+	copy(buf, t.data)
+	return nil
 }
 
 func (t *TestModel) Close(deviceID DeviceID, err error) {
diff --git a/nativemodel_darwin.go b/nativemodel_darwin.go
index 502a71f2..eb755a6e 100644
--- a/nativemodel_darwin.go
+++ b/nativemodel_darwin.go
@@ -26,9 +26,9 @@ func (m nativeModel) IndexUpdate(deviceID DeviceID, folder string, files []FileI
 	m.next.IndexUpdate(deviceID, folder, files, flags, options)
 }
 
-func (m nativeModel) Request(deviceID DeviceID, folder string, name string, offset int64, size int, hash []byte, flags uint32, options []Option) ([]byte, error) {
+func (m nativeModel) Request(deviceID DeviceID, folder string, name string, offset int64, hash []byte, flags uint32, options []Option, buf []byte) error {
 	name = norm.NFD.String(name)
-	return m.next.Request(deviceID, folder, name, offset, size, hash, flags, options)
+	return m.next.Request(deviceID, folder, name, offset, hash, flags, options, buf)
 }
 
 func (m nativeModel) ClusterConfig(deviceID DeviceID, config ClusterConfigMessage) {
diff --git a/nativemodel_unix.go b/nativemodel_unix.go
index 21585e30..0611865e 100644
--- a/nativemodel_unix.go
+++ b/nativemodel_unix.go
@@ -18,8 +18,8 @@ func (m nativeModel) IndexUpdate(deviceID DeviceID, folder string, files []FileI
 	m.next.IndexUpdate(deviceID, folder, files, flags, options)
 }
 
-func (m nativeModel) Request(deviceID DeviceID, folder string, name string, offset int64, size int, hash []byte, flags uint32, options []Option) ([]byte, error) {
-	return m.next.Request(deviceID, folder, name, offset, size, hash, flags, options)
+func (m nativeModel) Request(deviceID DeviceID, folder string, name string, offset int64, hash []byte, flags uint32, options []Option, buf []byte) error {
+	return m.next.Request(deviceID, folder, name, offset, hash, flags, options, buf)
 }
 
 func (m nativeModel) ClusterConfig(deviceID DeviceID, config ClusterConfigMessage) {
diff --git a/nativemodel_windows.go b/nativemodel_windows.go
index f1a24898..36a1d274 100644
--- a/nativemodel_windows.go
+++ b/nativemodel_windows.go
@@ -34,9 +34,9 @@ func (m nativeModel) IndexUpdate(deviceID DeviceID, folder string, files []FileI
 	m.next.IndexUpdate(deviceID, folder, files, flags, options)
 }
 
-func (m nativeModel) Request(deviceID DeviceID, folder string, name string, offset int64, size int, hash []byte, flags uint32, options []Option) ([]byte, error) {
+func (m nativeModel) Request(deviceID DeviceID, folder string, name string, offset int64, hash []byte, flags uint32, options []Option, buf []byte) error {
 	name = filepath.FromSlash(name)
-	return m.next.Request(deviceID, folder, name, offset, size, hash, flags, options)
+	return m.next.Request(deviceID, folder, name, offset, hash, flags, options, buf)
 }
 
 func (m nativeModel) ClusterConfig(deviceID DeviceID, config ClusterConfigMessage) {
diff --git a/protocol.go b/protocol.go
index d0e23055..8b41c013 100644
--- a/protocol.go
+++ b/protocol.go
@@ -81,7 +81,7 @@ type Model interface {
 	// An index update was received from the peer device
 	IndexUpdate(deviceID DeviceID, folder string, files []FileInfo, flags uint32, options []Option)
 	// A request was made by the peer device
-	Request(deviceID DeviceID, folder string, name string, offset int64, size int, hash []byte, flags uint32, options []Option) ([]byte, error)
+	Request(deviceID DeviceID, folder string, name string, offset int64, hash []byte, flags uint32, options []Option, buf []byte) error
 	// A cluster configuration message was received
 	ClusterConfig(deviceID DeviceID, config ClusterConfigMessage)
 	// The peer device closed the connection
@@ -112,11 +112,11 @@ type rawConnection struct {
 
 	idxMut sync.Mutex // ensures serialization of Index calls
 
-	nextID chan int
-	outbox chan hdrMsg
-	closed chan struct{}
-	once   sync.Once
-
+	nextID      chan int
+	outbox      chan hdrMsg
+	closed      chan struct{}
+	once        sync.Once
+	pool        sync.Pool
 	compression Compression
 
 	rdbuf0 []byte // used & reused by readMessage
@@ -129,8 +129,9 @@ type asyncResult struct {
 }
 
 type hdrMsg struct {
-	hdr header
-	msg encodable
+	hdr  header
+	msg  encodable
+	done chan struct{}
 }
 
 type encodable interface {
@@ -151,14 +152,19 @@ func NewConnection(deviceID DeviceID, reader io.Reader, writer io.Writer, receiv
 	cw := &countingWriter{Writer: writer}
 
 	c := rawConnection{
-		id:          deviceID,
-		name:        name,
-		receiver:    nativeModel{receiver},
-		cr:          cr,
-		cw:          cw,
-		outbox:      make(chan hdrMsg),
-		nextID:      make(chan int),
-		closed:      make(chan struct{}),
+		id:       deviceID,
+		name:     name,
+		receiver: nativeModel{receiver},
+		cr:       cr,
+		cw:       cw,
+		outbox:   make(chan hdrMsg),
+		nextID:   make(chan int),
+		closed:   make(chan struct{}),
+		pool: sync.Pool{
+			New: func() interface{} {
+				return make([]byte, BlockSize)
+			},
+		},
 		compression: compress,
 	}
 
@@ -195,7 +201,7 @@ func (c *rawConnection) Index(folder string, idx []FileInfo, flags uint32, optio
 		Files:   idx,
 		Flags:   flags,
 		Options: options,
-	})
+	}, nil)
 	c.idxMut.Unlock()
 	return nil
 }
@@ -213,7 +219,7 @@ func (c *rawConnection) IndexUpdate(folder string, idx []FileInfo, flags uint32,
 		Files:   idx,
 		Flags:   flags,
 		Options: options,
-	})
+	}, nil)
 	c.idxMut.Unlock()
 	return nil
 }
@@ -243,7 +249,7 @@ func (c *rawConnection) Request(folder string, name string, offset int64, size i
 		Hash:    hash,
 		Flags:   flags,
 		Options: options,
-	})
+	}, nil)
 	if !ok {
 		return nil, ErrClosed
 	}
@@ -257,7 +263,7 @@ func (c *rawConnection) Request(folder string, name string, offset int64, size i
 
 // ClusterConfig send the cluster configuration message to the peer and returns any error
 func (c *rawConnection) ClusterConfig(config ClusterConfigMessage) {
-	c.send(-1, messageTypeClusterConfig, config)
+	c.send(-1, messageTypeClusterConfig, config, nil)
 }
 
 func (c *rawConnection) ping() bool {
@@ -273,7 +279,7 @@ func (c *rawConnection) ping() bool {
 	c.awaiting[id] = rc
 	c.awaitingMut.Unlock()
 
-	ok := c.send(id, messageTypePing, nil)
+	ok := c.send(id, messageTypePing, nil, nil)
 	if !ok {
 		return false
 	}
@@ -342,7 +348,7 @@ func (c *rawConnection) readerLoop() (err error) {
 			if state != stateReady {
 				return fmt.Errorf("protocol error: ping message in state %d", state)
 			}
-			c.send(hdr.msgID, messageTypePong, pongMessage{})
+			c.send(hdr.msgID, messageTypePong, pongMessage{}, nil)
 
 		case pongMessage:
 			if state != stateReady {
@@ -519,12 +525,36 @@ func filterIndexMessageFiles(fs []FileInfo) []FileInfo {
 }
 
 func (c *rawConnection) handleRequest(msgID int, req RequestMessage) {
-	data, err := c.receiver.Request(c.id, req.Folder, req.Name, int64(req.Offset), int(req.Size), req.Hash, req.Flags, req.Options)
+	size := int(req.Size)
+	usePool := size <= BlockSize
 
-	c.send(msgID, messageTypeResponse, ResponseMessage{
-		Data: data,
-		Code: errorToCode(err),
-	})
+	var buf []byte
+	var done chan struct{}
+
+	if usePool {
+		buf = c.pool.Get().([]byte)[:size]
+		done = make(chan struct{})
+	} else {
+		buf = make([]byte, size)
+	}
+
+	err := c.receiver.Request(c.id, req.Folder, req.Name, int64(req.Offset), req.Hash, req.Flags, req.Options, buf)
+	if err != nil {
+		c.send(msgID, messageTypeResponse, ResponseMessage{
+			Data: nil,
+			Code: errorToCode(err),
+		}, done)
+	} else {
+		c.send(msgID, messageTypeResponse, ResponseMessage{
+			Data: buf,
+			Code: errorToCode(err),
+		}, done)
+	}
+
+	if usePool {
+		<-done
+		c.pool.Put(buf)
+	}
 }
 
 func (c *rawConnection) handleResponse(msgID int, resp ResponseMessage) {
@@ -547,7 +577,7 @@ func (c *rawConnection) handlePong(msgID int) {
 	c.awaitingMut.Unlock()
 }
 
-func (c *rawConnection) send(msgID int, msgType int, msg encodable) bool {
+func (c *rawConnection) send(msgID int, msgType int, msg encodable, done chan struct{}) bool {
 	if msgID < 0 {
 		select {
 		case id := <-c.nextID:
@@ -564,7 +594,7 @@ func (c *rawConnection) send(msgID int, msgType int, msg encodable) bool {
 	}
 
 	select {
-	case c.outbox <- hdrMsg{hdr, msg}:
+	case c.outbox <- hdrMsg{hdr, msg, done}:
 		return true
 	case <-c.closed:
 		return false
@@ -583,6 +613,9 @@ func (c *rawConnection) writerLoop() {
 			if hm.msg != nil {
 				// Uncompressed message in uncBuf
 				uncBuf, err = hm.msg.AppendXDR(uncBuf[:0])
+				if hm.done != nil {
+					close(hm.done)
+				}
 				if err != nil {
 					c.close(err)
 					return