Hi Fairle, ¿Why you aren't collecting system stats? You could save your current stats, give a shot to system stats for a while, and then compare.. alvaro All, Environment: 8 node RAC on Solaris Sun sparc 9 64 bit Database : 10.2.0.3 RAC Customer is upgrading CPU boards from Sparc IV to Sparc IV pluses. There is no change in the number of cpus. Assuming there is no collection of system stats (which could thus affect query plans) can anyone think of any other issues...in doing this upgrade... Also is anyone out there using Sparc IV pluses.