The SSIS pipeline is being changed in Katmai to allow
more parallel processing. For any multi processor machine this should result in
a performance improvement.
Essentially each arrow in your data flow can now have an active buffer, where
as in SQL 2005 you only have 1 active buffer from the source to the next
asynchronous component. Many people put in a UNION ALL component (which is
asynchronous) to allow more buffers to be used.
This means the multicast will be able to have an active buffer on each output
and not just have 1 buffer which is passed to each output.
I haven't yet played with this but I'm really excited.
For example a flow with 4 lookups currently only has data processed by one
lookup at a time, this should enable each lookup to be processing data.
For more infor read Michael's post http://blogs.msdn.com/michen/archive/2007/06/11/katmai-ssis-data-flow-improvements.aspx