--- a/netwerk/protocol/http/nsHttpHandler.cpp
+++ b/netwerk/protocol/http/nsHttpHandler.cpp
@@ -780,17 +780,17 @@ nsHttpHandler::InitUserAgentComponents()
         if (strcmp(name.machine, "x86_64") == 0 &&
             sizeof(void *) == sizeof(PRInt32)) {
             // We're running 32-bit code on x86_64. Make this browser
             // look like it's running on i686 hardware, but append "
             // (x86_64)" to the end of the oscpu identifier to be able
             // to differentiate this from someone running 64-bit code
             // on x86_64..
 
-            buf += " i686 (x86_64)";
+            buf += " i686 on x86_64";
         } else {
             buf += ' ';
 
 #ifdef AIX
             // AIX uname returns machine specific info in the uname.machine
             // field and does not return the cpu type like other platforms.
             // We use the AIX version and release numbers instead.
             buf += (char*)name.version;