When I choose tree-view in at the left side of thunar and when I am surfing by folders I can feel real terrible slowings. I use reiserfs. At the / directory it is OK. and when i am going down to /usr/src/linux-2.6.28.3 (for example) i can feel more and more slowness. at the end I can't wait so long I have to close the thunar window. it doesn't changes anything an d i must kill thunar process. then it goes to speed-up.