AJAX: Sync faster than than Async?

AJAX: Sync faster than than Async?

You wouldn't think so, but in Chromes Developer Tools Network tab, I can see Async: false returning results faster then Async : true.  I want to use Async:true, but is it slower... (and wont lock the browser).  These are NOT time intensive calls..  Async avg = 800ms,  Sync avg 300ms.  I'm running 9 requests simultaneously, because of the 6 simultaneous connects limit, I see 3 are queued when running Async.
FYI: jquery-1.6.2 

Any explanation why Async:true is slower?  
I can publish snapshots of the Network results if needed, the only thing changes is Async: true/false