--- a/ExternalStream.st	Thu Mar 31 17:33:05 2016 +0200
+++ b/ExternalStream.st	Fri Apr 01 00:03:04 2016 +0200
@@ -2958,13 +2958,16 @@
 
     |bufferSize|
 
-    OperatingSystem isMSDOSlike ifTrue:[
-	"/ mhmh - NT hangs, when copying bigger blocks to a network drive - why ?
-	bufferSize := 1 * 1024.
-    ] ifFalse:[
-	bufferSize := 8 * 1024.
+    (self isFileStream and:[outStream isFileStream]) ifTrue:[
+        bufferSize := 8192 * 8.     "/ 64k buffer size
+    ] ifFalse:[    
+        OperatingSystem isMSDOSlike ifTrue:[
+            "/ mhmh - NT hangs, when copying bigger blocks to a network drive - why ?
+            bufferSize := 1 * 1024.
+        ] ifFalse:[
+            bufferSize := 8 * 1024.
+        ].
     ].
-
     ^ self copyToEndInto:outStream bufferSize:bufferSize
 
     "