I'm wondering if having a very large - 1.5G - buffer cache can effect cpu usage. One of our production servers has 80000 db_block_buffers with a block size 0f 8k. I used the follwoing query to find out the status of the buffers.

select decode(state, 0, 'Free', 1,
decode(lrba_seq,0,'Available','Being Modified'),
2, 'Not Modified',
3, 'Being Read', 'Other') "BLOCK STATUS",
count(*) cntfrom sys.x$bh
group by decode(state, 0, 'Free',1, decode(lrba_seq,0,'Available','Being Modified'),
2, 'Not Modified',3, 'Being Read','Other')

-------------- ----------
Available 79430
Being Modified 331
Being Read 239

If i reduce the db_block_buffers from 80000 to 60000 will this have an impaceon the performance. Based upon the count from the above it looks like the buffer cache is oversized.

Any help would be greatly appreciated.

Thanks in Advance.