Deserializing Generic List taking a lot of time

[C# Programming]

Hello Guys,

Need some help from you guys.

I have Generic List having a Class object.
I have added around 3000000 items in the list

List lsTemp = new List ();

when i tried to Serialize the with binary formater it is working fine

but when I deserialize the List it takes a lot of time around 30 Seconds.

But when i fill the Generic List with any datatype like

List lsTemp = new List();

and follow the same procedure the speed difference is drastic the while thing deserializes in 1 -2 Seconds

My Class object is Declared Serializable.

I dont understand why it is serialzer is behaving like this.

Am i Missing something.

Here is the Sample Code :

List lsTemp = new List();

for(int i=0; i < 5000000;i++)
{
CTempClass oTemp = new CTempClass();
oTemp.ID = i;
lsTemp.Add(oTemp);
oTemp=null;
}

using (Stream stream = File.Open("c:\\data.bin", FileMode.CreateNew))
{
BinaryFormatter bin = new BinaryFormatter();
bin.Serialize(stream, lsTemp );

}

//this takes a lot of time
using (Stream stream = File.Open("c:\\data.bin", FileMode.Open))
{
BinaryFormatter bin = new BinaryFormatter();
var lsTemp1 = bin.Deserialize(stream);

}

here is the code of temp class
[Serializable]
public class CTempClass : ISerializable
{
// public int nId;


private ulong m_uCrc64;

public CTempClass ()
{
m_uCrc64 = 0;
}

//Deserialization constructor.
public CTempClass (SerializationInfo info, StreamingContext ctxt)
{
//Get the values from info and assign them to the appropriate properties
m_uCrc64 = info.GetUInt64("m_uCrc64");

}

//Serialization function.
public void GetObjectData(SerializationInfo info, StreamingContext ctxt)
{

info.AddValue("m_uCrc64", m_uCrc64);

}

}

Can any one please tell me why it is taking so much of time.
Any suggestion will be a great help

abhinav