I know other things are running on the server but it is SQL that is in a twist.  It CPU spikes to 100% for the entire duration of the execution. ...

It's a batch that calls stored procedures.  The cause is not fragmented indexes or stats because a series of executions will run at 3 or 4 seconds.  Then a series...

No difference in the SQL, parameters or execution plan. I don't think the execution plan is the problem here.  I think a part of the architecture that takes over after the optimiser...

Not only is the T-SQL exactly the same but the execution plan is exactly the same including paths, estimates etc.  This is what has lead me to question wether there...

Woops, please ignore - I'm using 2000

I have fixed this myself .  This fix is SharePoint specific so a lot of what follows will...

I don't have that registry key!  I have tried creating it and setting it to 256, 512 and 2560 but it makes no difference.  The total size of all my...