diff --git a/v2rayN/v2rayN/Forms/MainForm.cs b/v2rayN/v2rayN/Forms/MainForm.cs
index 042159c6..c2f749a8 100644
--- a/v2rayN/v2rayN/Forms/MainForm.cs
+++ b/v2rayN/v2rayN/Forms/MainForm.cs
@@ -977,9 +977,9 @@ namespace v2rayN.Forms
         }
         private void ClearTestResult()
         {
-            for (int k = 0; k < lvSelecteds.Count; k++)
+            foreach (int s in lvSelecteds)
             {
-                SetTestResult(lvSelecteds[k], "");
+                SetTestResult(s, "");
             }
         }
         private void UpdateSpeedtestHandler(int index, string msg)
diff --git a/v2rayN/v2rayN/Handler/SpeedtestHandler.cs b/v2rayN/v2rayN/Handler/SpeedtestHandler.cs
index 295650b0..367b198b 100644
--- a/v2rayN/v2rayN/Handler/SpeedtestHandler.cs
+++ b/v2rayN/v2rayN/Handler/SpeedtestHandler.cs
@@ -103,9 +103,8 @@ namespace v2rayN.Handler
         {
             try
             {
-                for (int k = 0; k < _selecteds.Count; k++)
+                foreach (int index in _selecteds)
                 {
-                    int index = _selecteds[k];
                     if (_config.vmess[index].configType == (int)EConfigType.Custom)
                     {
                         continue;
@@ -121,7 +120,7 @@ namespace v2rayN.Handler
                     }
                 }
 
-                Thread.Sleep(100);
+                Thread.Sleep(10);
 
             }
             catch (Exception ex)
@@ -262,8 +261,14 @@ namespace v2rayN.Handler
                 var timer = new Stopwatch();
                 timer.Start();
 
-                Socket clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
-                clientSocket.Connect(new IPEndPoint(ipAddress, port));
+                var endPoint = new IPEndPoint(ipAddress, port);
+                Socket clientSocket = new Socket(endPoint.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
+
+                IAsyncResult result = clientSocket.BeginConnect(endPoint, null, null);
+                if (!result.AsyncWaitHandle.WaitOne(TimeSpan.FromSeconds(5)))
+                    throw new TimeoutException("connect timeout (5s): " + url);
+                clientSocket.EndConnect(result);
+
                 timer.Stop();
                 responseTime = timer.Elapsed.Milliseconds;
                 clientSocket.Close();