cassandra slow write

[ROGER PUIG GANZA]

Hello, I' doing some tests with Cassandra, but I get a very slow performance, 
it does 100.000 inserts in 215 seconds while mysql takes 79 secs
The code below is the one I'm using, is there anything wrong with my Cassandra 
or java understanding?
The configuration-file params are the default ones.
Thank you!

cassandraInserter(){
long ini = System.currentTimeMillis();
            TTransport tr = new TSocket(ip, port);
            TBinaryProtocol proto = new TBinaryProtocol(tr);
            Client client = new Client(proto);

            try {
                  tr.open();
            } catch (TTransportException e1) {
                  e1.printStackTrace();
            }

            for (int i = 0; i < N; i++) {
                  try {
                        long timestamp = System.currentTimeMillis();
                        List<ColumnOrSuperColumn> columns = new 
ArrayList<ColumnOrSuperColumn>();
                        Map<String, List<ColumnOrSuperColumn>> map = new 
HashMap<String, List<ColumnOrSuperColumn>>();

                        columns.add(new ColumnOrSuperColumn(new Column(col1, 
data, timestamp), null));
                        columns.add(new ColumnOrSuperColumn(new Column(col2, 
data, timestamp), null));
                        columns.add(new ColumnOrSuperColumn(new Column(col3, 
data, timestamp), null));
                        columns.add(new ColumnOrSuperColumn(new Column(col4, 
data, timestamp), null));
                        columns.add(new ColumnOrSuperColumn(new Column(col4, 
data, timestamp), null));
                        columns.add(new ColumnOrSuperColumn(new Column(col5, 
data, timestamp), null));
                        columns.add(new ColumnOrSuperColumn(new Column(col6, 
data, timestamp), null));
                        columns.add(new ColumnOrSuperColumn(new Column(col7, 
data, timestamp), null));
                        columns.add(new ColumnOrSuperColumn(new Column(col8, 
data, timestamp), null));
                        acl.put(colfamily, columns);
                        client.batch_insert(keyspace, key, map, 
ConsistencyLevel.ONE);
                  } catch (TTransportException e) {
                        e.printStackTrace();
                  } catch (UnsupportedEncodingException e) {
                        e.printStackTrace();
                  } catch (InvalidRequestException e) {
                        e.printStackTrace();
                  } catch (UnavailableException e) {
                        e.printStackTrace();
                  } catch (TException e) {
                        e.printStackTrace();
                  }
            }
            tr.close();
      }

Roger Puig Ganza