Access v$system_event so slowly.

I am writing a tool to repeatly display the v$system_event information (the changed value), I try to display it every 5 seconds, but the query need to run 2-3 seconds, v$system_event have only about 400 rows.

When I access v$SQL, it's faster than the v$system_event.

SELECT /* OPMON WAIT EVENT */ /*+ rule */

          n.name,
          nvl(e.total_waits,0) waits,
          nvl(e.time_waited,0) wtime
        FROM V$SYSTEM_EVENT e, V$EVENT_NAME N
        WHERE N.NAME = E.EVENT(+)
              AND N.NAME NOT LIKE '%timer'
              AND N.NAME NOT LIKE 'rdbms%message%'
              AND N.NAME NOT LIKE '_ull event'
              AND N.NAME NOT LIKE 'SQL*Net%message%client'
              AND N.NAME NOT LIKE 'client%message'
              AND N.NAME NOT LIKE '%Idle Wait'
              AND N.NAME NOT LIKE '%idle wait'
              AND N.NAME NOT LIKE 'lock%manager%remote%message'
              AND N.NAME NOT LIKE '%slave wait'
              AND N.NAME NOT LIKE '%Slave Wait'
              AND N.NAME NOT LIKE 'PX Deq%'
              AND N.NAME NOT LIKE 'wakeup%'
              AND N.NAME NOT LIKE 'Queue Monitor%'
              AND N.NAME NOT LIKE 'pipe get'
              AND N.NAME NOT LIKE '%remote%message'
              AND N.NAME NOT LIKE '%queue%message%'
              AND N.NAME NOT LIKE '%wait%message%'
              AND N.NAME <> 'knlqdeq'
        UNION ALL
        SELECT 'CPU time',0,VALUE
          FROM V$SYSSTAT 
        WHERE NAME='CPU used by this session'