If you are running a 32-bit based Poser version, set your General Preferences settings for the library to use Adobe Air rather than Adobe Flash.  This will undock the Library as a separate feature and eliminate the slow down.  

After loading Michael 6, go to the DSON Importer script and set the subdivision to 0, this will also offset any app slowdown when adding content and posing.

And download Dimension3D's DSONLoader (Free) from here:

http://d3d.sesseler.de/index.php?software=poserpython&product=dson_loader

This is a wonderful, useful script which will load DSON files into Poser when PCF is not available for certain content.  Otherwise, PCF would need to be generated through DAZStudio and saved to Poser.  This process is much more involved and requires a better understanding using DAZStudio.