I've inherited 2 instances of SQL 2008 R2 Enterprise (64bit) both "apparently" running on the same box - I don't have physical access to the box.
From SSMS I can see
Instance 1 has the following items ticked
CPU 3,4,5,6 and 15,16,17,18 Processor affinity.
Automatically set I/O affinity mask for all processors.
Instance 2 has the following items ticked
CPU 9,10,11 and 21,22,23
Automatically set I/O affinity mask for all processors.
My question is - as both the Automatically set I/O options are ticked for both - could this be having a detrimental affect on either of the instances ? as we experience considerable slow down at various times throughout the day (although not consistently the same time)