chris 76827 (8/13/2012)
Yeah sorry I appreciate its all done in memory but I was referring to the write back stage.That's pretty much answered my question, cheers.
That does not mean that you should not do the check though:
update x
set y = 3
where y <> 3 or y is null
will run faster, in my experience, than
update x
set y = 3
especially if many of the rows are already 3.
If you haven't even tried to resolve your issue, please don't expect the hard-working volunteers here to waste their time providing links to answers which you could easily have found yourself.