diff --git a/src/NmeaParser.Shared/BufferedStreamDevice.cs b/src/NmeaParser.Shared/BufferedStreamDevice.cs
index b230f26..aa103d2 100644
--- a/src/NmeaParser.Shared/BufferedStreamDevice.cs
+++ b/src/NmeaParser.Shared/BufferedStreamDevice.cs
@@ -34,13 +34,13 @@ namespace NmeaParser
 		/// <summary>
 		/// Initializes a new instance of the <see cref="BufferedStreamDevice"/> class.
 		/// </summary>
-		protected BufferedStreamDevice() : this(200)
+		protected BufferedStreamDevice() : this(1000)
 		{
 		}
 		/// <summary>
 		/// Initializes a new instance of the <see cref="BufferedStreamDevice"/> class.
 		/// </summary>
-		/// <param name="readSpeed">The time to wait between each line being read in milliseconds</param>
+		/// <param name="readSpeed">The time to wait between each group of lines being read in milliseconds</param>
 		protected BufferedStreamDevice(int readSpeed)
 		{
 			m_readSpeed = readSpeed;
@@ -77,30 +77,50 @@ namespace NmeaParser
 		}
 
 		// stream that slowly populates a buffer from a StreamReader to simulate nmea messages coming
-		// in line by line at a steady stream
+		// in lastLineRead by lastLineRead at a steady stream
 		private class BufferedStream : Stream
 		{
-			StreamReader m_sr;
-			byte[] m_buffer = new byte[0];
-			System.Threading.Timer m_timer;
-			object lockObj = new object();
+			private StreamReader m_sr;
+			private byte[] m_buffer = new byte[0];
+			private System.Threading.Timer m_timer;
+			private object lockObj = new object();
+			private string groupToken = null;
+			private string lastLineRead = null;
 			/// <summary>
 			/// Initializes a new instance of the <see cref="BufferedStream"/> class.
 			/// </summary>
 			/// <param name="stream">The stream.</param>
-			/// <param name="readSpeed">The read speed.</param>
+			/// <param name="readSpeed">The read speed in milliseconds.</param>
 			public BufferedStream(StreamReader stream, int readSpeed)
 			{
 				m_sr = stream;
-				m_timer = new System.Threading.Timer(OnRead, null, 0, readSpeed); //add a new line to buffer every 100 ms
+				m_timer = new System.Threading.Timer(OnRead, null, 0, readSpeed); //read a group of lines every 'readSpeed' milliseconds
 			}
 			private void OnRead(object state)
 			{
-				if (m_sr.EndOfStream)
-					m_sr.BaseStream.Seek(0, SeekOrigin.Begin); //start over
-
-				//populate the buffer with a line
-				string line = m_sr.ReadLine() + '\n';
+				if (lastLineRead != null)
+					AppendToBuffer(lastLineRead);
+				//Get the group token if we don't have one
+				while (groupToken == null && (lastLineRead == null || !lastLineRead.StartsWith("$", StringComparison.Ordinal)))
+				{
+					lastLineRead = ReadLine(); //seek forward to first nmea token
+					AppendToBuffer(lastLineRead);
+				}
+				if(groupToken == null)
+				{
+					var values = lastLineRead.Trim().Split(new char[] { ',' });
+					if (values.Length > 0)
+						groupToken = values[0];
+				}
+				lastLineRead = ReadLine();
+				while (!lastLineRead.StartsWith(groupToken, StringComparison.Ordinal)) //keep reading until messages start repeating again
+				{
+					AppendToBuffer(lastLineRead);
+					lastLineRead = ReadLine();
+				}				
+			}
+			private void AppendToBuffer(string line)
+			{
 				var bytes = Encoding.UTF8.GetBytes(line);
 				lock (lockObj)
 				{
@@ -110,6 +130,12 @@ namespace NmeaParser
 					m_buffer = newBuffer;
 				}
 			}
+			private string ReadLine()
+			{
+				if (m_sr.EndOfStream)
+					m_sr.BaseStream.Seek(0, SeekOrigin.Begin); //start over
+				return m_sr.ReadLine() + '\n';
+			}
 			/// <summary>
 			/// Gets a value indicating whether this instance can read.
 			/// </summary>
diff --git a/src/NmeaParser.Shared/NmeaDevice.cs b/src/NmeaParser.Shared/NmeaDevice.cs
index 5e8c119..10ae92d 100644
--- a/src/NmeaParser.Shared/NmeaDevice.cs
+++ b/src/NmeaParser.Shared/NmeaDevice.cs
@@ -81,7 +81,7 @@ namespace NmeaParser
 					{
 						OnData(buffer.Take(readCount).ToArray());
 					}
-					await Task.Delay(10, token);
+					await Task.Delay(50, token);
 				}
 				if (closeTask != null)
 					closeTask.SetResult(true);
@@ -123,19 +123,22 @@ namespace NmeaParser
 		private void OnData(byte[] data)
 		{
 			var nmea = System.Text.Encoding.UTF8.GetString(data, 0, data.Length);
-			string line = null;
+			List<string> lines = new List<string>();
 			lock (m_lockObject)
 			{
 				m_message += nmea;
 
 				var lineEnd = m_message.IndexOf("\n", StringComparison.Ordinal);
-				if (lineEnd > -1)
+				while (lineEnd > -1)
 				{
-					line = m_message.Substring(0, lineEnd).Trim();
+					string line = m_message.Substring(0, lineEnd).Trim();
 					m_message = m_message.Substring(lineEnd + 1);
+					if (!string.IsNullOrEmpty(line))
+						lines.Add(line);
+					lineEnd = m_message.IndexOf("\n", StringComparison.Ordinal);
 				}
 			}
-			if (!string.IsNullOrEmpty(line))
+			foreach(var line in lines)
 				ProcessMessage(line);
 		}
 
diff --git a/src/NmeaParser.Shared/NmeaFileDevice.cs b/src/NmeaParser.Shared/NmeaFileDevice.cs
index 77195ae..12ab88a 100644
--- a/src/NmeaParser.Shared/NmeaFileDevice.cs
+++ b/src/NmeaParser.Shared/NmeaFileDevice.cs
@@ -39,9 +39,9 @@ namespace NmeaParser
 		/// </summary>
 		/// <param name="fileName"></param>
 #if NETFX_CORE
-		public NmeaFileDevice(Windows.Storage.IStorageFile fileName) : this(fileName, 200)
+		public NmeaFileDevice(Windows.Storage.IStorageFile fileName) : this(fileName, 1000)
 #else
-		public NmeaFileDevice(string fileName) : this(fileName, 200)
+		public NmeaFileDevice(string fileName) : this(fileName, 1000)
 #endif
 		{
 			m_filename = fileName;
@@ -50,7 +50,7 @@ namespace NmeaParser
 		/// Initializes a new instance of the <see cref="NmeaFileDevice"/> class.
 		/// </summary>
 		/// <param name="fileName"></param>
-		/// <param name="readSpeed">The time to wait between each line being read in milliseconds</param>
+		/// <param name="readSpeed">The time to wait between each group of lines being read in milliseconds</param>
 #if NETFX_CORE
 		public NmeaFileDevice(Windows.Storage.IStorageFile fileName, int readSpeed)
 			: base(readSpeed)
@@ -62,7 +62,6 @@ namespace NmeaParser
 		}
 
 #if !NETFX_CORE
-
 		/// <summary>
 		/// Gets the name of the nmea file this device is using.
 		/// </summary>