Which udma mode are you using on your a1? On my sil0680 i'm using udma mode 1.In the beginning i was using best pio,cos i had heard it might not work with udma on my SE. Offcourse pio mode is slow,so i tried experimenting. I set it to udma0,it worked,so a couple of days ago i set it to 1. When using ctorrent on best pio it used 100%cpu when creating the files on my hd,on udma1 it used only 50%,and it was quicker
.. So i'll now try to set it to udma2 and see how it workes.