** CPU impact of I/O change

Hi,

     I plan to make changes to database like increase SGA, save rows of some tables : then do truncate of table and insert the rows back or move table to reduce HWM and to take care of chained rows. All this will help reduce the I/O done. There are some full table scans and some index accesses. My question is : What impact will this change in I/O have on CPU usage. Improvement, no impact or adverse? Anything else to look at or watch out for? Thanks                  

--
http://www.freelists.org/webpage/oracle-l