I suspect 2 things:
- qt3/x11 is heavier than qt2/qt/e (it might depends also on how qt is compiled)
- though I don't know how this works, I could be totally wrong, I think that in sharp roms the qt libs are allways " loaded", while in pdaxrom it might not be the case as there are not so many qt applications.
rmrfchick has suggested to use prelink to speeds things up, but compiling prelink for arm seems to be a bit tricky...