XAttributes are slow. Or is it just me?

I am building process to read large DGN's with XAttributes on each element, then do some minor mods the the element (which is not the slow part).

Seems to not be very quick at extracting the XML string.  I think I have made it reasonably efficient by only setting up the Schema Manager and InstanceApi once then reading each instance as each element is scanned.

Does anyone have experience with large data sets?