diff --git a/backend/azureblob/azureblob.go b/backend/azureblob/azureblob.go
index 9ff23eecf..8a3b0b36d 100644
--- a/backend/azureblob/azureblob.go
+++ b/backend/azureblob/azureblob.go
@@ -157,7 +157,7 @@ raise this to 64. Note that this will use more memory.
 Note that chunks are stored in memory and there may be up to
 "--transfers" * "--azureblob-upload-concurrency" chunks stored at once
 in memory.`,
-			Default:  4,
+			Default:  16,
 			Advanced: true,
 		}, {
 			Name: "list_chunk",
diff --git a/docs/content/azureblob.md b/docs/content/azureblob.md
index f4323929e..96d8a0acd 100644
--- a/docs/content/azureblob.md
+++ b/docs/content/azureblob.md
@@ -81,6 +81,14 @@ key.  It is stored using RFC3339 Format time with nanosecond
 precision.  The metadata is supplied during directory listings so
 there is no overhead to using it.
 
+### Performance
+
+When uploading large files, increasing the value of
+`--azureblob-upload-concurrency` will increase performance at the cost
+of using more memory. The default of 16 is set quite conservatively to
+use less memory. It maybe be necessary raise it to 64 or higher to
+fully utilize a 1 GBit/s link with a single file transfer.
+
 ### Restricted filename characters
 
 In addition to the [default restricted characters set](/overview/#restricted-characters)