diff --git a/uploader/multipart.go b/uploader/multipart.go
index fb6be22..cda4b34 100644
--- a/uploader/multipart.go
+++ b/uploader/multipart.go
@@ -16,7 +16,8 @@ type MultipartFile interface {
 
 func fetchMultipartFile(l *zap.Logger, r io.Reader, boundary string) (MultipartFile, error) {
 	// To have a custom buffer (3mb) the custom multipart reader is used.
-	// https://github.com/nspcc-dev/neofs-http-gw/issues/148
+	// Default reader uses 4KiB chunks, which slow down upload speed up to 400%
+	// https://github.com/golang/go/blob/91b9915d3f6f8cd2e9e9fda63f67772803adfa03/src/mime/multipart/multipart.go#L32
 	reader := multipart.NewReader(r, boundary)
 
 	for {