diff --git a/src/global.h b/src/global.h
index bdb12169..1124fe82 100755
--- a/src/global.h
+++ b/src/global.h
@@ -73,7 +73,7 @@
 #define DEF_NET_BLOCK_SIZE_FACTOR       3
 
 // maximum network buffer size (which can be chosen by slider)
-#define MAX_NET_BUF_SIZE_NUM_BL         10 // number of blocks
+#define MAX_NET_BUF_SIZE_NUM_BL         12 // number of blocks
 
 // default network buffer size
 #define DEF_NET_BUF_SIZE_NUM_BL         6 // number of blocks
diff --git a/src/server.cpp b/src/server.cpp
index a53c83ae..eb44ce3e 100755
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -106,7 +106,7 @@ void CServer::Start()
         Timer.start ( MIN_BLOCK_DURATION_MS );
 
         // init time for response time evaluation
-        TimeLastBlock = QTime::currentTime();
+        TimeLastBlock = PreciseTime.elapsed();
         RespTimeMoAvBuf.Reset();
     }
 }
@@ -173,12 +173,12 @@ void CServer::OnTimer()
 
     // update response time measurement ----------------------------------------
     // add time difference
-    const QTime CurTime = QTime::currentTime();
+    const int CurTime = PreciseTime.elapsed();
 
     // we want to calculate the standard deviation (we assume that the mean
     // is correct at the block period time)
-    const double dCurAddVal = ( (double) TimeLastBlock.msecsTo ( CurTime ) -
-        MIN_BLOCK_DURATION_MS );
+    const double dCurAddVal =
+        ( (double) ( CurTime - TimeLastBlock ) - MIN_BLOCK_DURATION_MS );
 
     RespTimeMoAvBuf.Add ( dCurAddVal * dCurAddVal ); // add squared value
 
diff --git a/src/server.h b/src/server.h
index 401de0ff..98a2aadd 100755
--- a/src/server.h
+++ b/src/server.h
@@ -79,8 +79,9 @@ protected:
     CSocket             Socket;
 
     // debugging, evaluating
+    CPreciseTime        PreciseTime;
     CMovingAv<double>   RespTimeMoAvBuf;
-    QTime               TimeLastBlock;
+    int                 TimeLastBlock;
 
     // logging
     CLogging            Logging;