min(starttime), max(endtime))...

I don't have a copy of the trace but if you have open connections for a few minutes before starting the "real" work or a few minutes after the end or anything else unexpected, you'll get a longer duration than what actually happened during the real test.

That's why I preffer to use start/stop time in a script or just a stop watch. My idea was just to do a sum of endtime - startime for all 68 M queries... this figure "should" match sum(Duration) / 1000.

If parralelism is off... or not used for some reason it duplicates the available minutes of processing power.

For my rounding theory I have no idea how it affects traces with 2005 and 2008 but I have the feeling it may with my experience in 2000.

I think that if you add up all the possible causes you have a probable explaination... 8 cores meaning 8 secs of potential processing per "real time" second + even 0.1 MS rounding error in the data could account for 100% of the discrepency you experience.

As annoying as those figures are. I agree with Brad's avice that you should just go with optimizing the most ressources and time hungry queries and let go of this issue, if only for your mental health! :w00t: