File conversion from wav to MP3 - why does it take so long?

When I convert a .wav file to an MP3 file (256kbps or 320kbps),  the average song file takes way longer to convert in Pyro than in, say, iTunes' conversion app.  Is there any way to get faster conversion time out of Pyro? Example I just did a comparison converting the wav of the same song first using Pyro AC and it took about 2.5 minutes, then did the same over in iTunes in about 30 seconds. And I had just downloaded & installed the latest update, no improvement.  Running on Windows XP.   I like using Pyro, especially the editing, track overlapping, etc. but the slow conversion is quite annoying.  Thanks in advance for any suggestions. 

I'd recommend trying Audio Converter Studio. It's a universal tool with batch processing and folder structure creating functions available. Might help you as well as it helped me.