associating binding array - poor performance

Dear All
i have very very low performence when i am inserting a binary array using associative array bind. i mean when i insert huge jagged binary array.
the jagged array has


BinarryArray[0][0]........BinarryArray[0][8000]
BinarryArray[1][0]........BinarryArray[1][8000]
....
....
....
BinarryArray[3600][0]........BinarryArray[3600][8000]

BinarryArray[0] - i have 8000 byte end so on. total is 3600 X 8000
that means 28,800KB hence to ~28MB.

the C# code is as follows

string strInsert "Insert Into T Values(t.SEQUENCE.currval, :paramArr);

OracleCommand objCommand = new OracleCommand;

OracleParameter objParam = new OracleParameter(paramArr, OracleDbtype.blob, 8000, system.data.ParameterDirection.Input,true,0,0,"ColumnName", system.data.DataRowVersion.Curren, BinarryArray);

objCommandtext = strInsert;

objCommand.ArrayBindCount = BinarryArray.Length;

objCommand.Parameters.Clear();
objCommand.Parameters.Add(paramArr);


objCommand.ExecuteNonQuery();

In generall the Insertion is good for each row in the array i get separate row in the DB but it works so slow.
why??????