Compared to 1.0, 2.0a3 uses a lot more CPU time when something is written on the console during the compilation.
I use the hyphenat package with the htt option, which results in a lot of "Underfull \hbox"-lines (approx. 2000). While they are printed in the result window, pdflatex stops completely and Texniccenter runs at 100% CPU load.
I added a screenshot from Process Explorer. pdflatex.exe is marked red because it ends in the second I made the screenshot. The complete run takes about 1:05 min