How should I multiple insert multiple records?

I have a class named Entry declared like this:

class Entry{    string Id {get;set;}    string Name {get;set;}}  

and then a method that will accept multiple such Entry objects for insertion into the database using ADO.NET:

static void InsertEntries(IEnumerable<Entry> entries){    //build a SqlCommand object    using(SqlCommand cmd = new SqlCommand()){        ...        const string refcmdText = "INSERT INTO Entries (id, name) VALUES (@id{0},@name{0});";        int count = 0;        string query = string.Empty;        //build a large query        foreach(var entry in entries){            query += string.Format(refcmdText, count);            cmd.Parameters.AddWithValue(string.Format("@id{0}",count), entry.Id);            cmd.Parameters.AddWithValue(string.Format("@name{0}",count), entry.Name);            count++;        }        cmd.CommandText=query;        //and then execute the command        ...    }}  

And my question is this: should I keep using the above way of sending multiple insert statements (build a giant string of insert statements and their parameters and send it over the network), or should I keep an open connection and send a single insert statement for each Entry like this:

using(SqlCommand cmd = new SqlCommand(){    using(SqlConnection conn = new SqlConnection(){        //assign connection string and open connection        ...        cmd.Connection = conn;        foreach(var entry in entries){            cmd.CommandText= "INSERT INTO Entries (id, name) VALUES (@id,@name);";            cmd.Parameters.AddWithValue("@id", entry.Id);            cmd.Parameters.AddWithValue("@name", entry.Name);            cmd.ExecuteNonQuery();        }    } }  

What do you think? Will there be a performance difference in the Sql Server between the two? Are there any other consequences I should be aware of?