HTML5 and LMS

SL3 Experts,

Recently upgraded to SL3 from 2 and I make extensive use of fade transitions applied to all slides in my SL3 projects. I never had problems with published output in SL2 using Flash with HTML5 backup. Now in SL3 and publishing in pure HTML5 at client request, we're having issues with LMS lag and delay specifically due to the fade transitions. If the transitions are removed, or if we publish with Flash primary, the output is trouble-free. Put them back in and the lag is unacceptable. Has anyone else had problems with this? Sorry if this has been discussed- I searched the forum pretty hard, but came up empty.