Yes, pifast is indeed an ugly wench... I found that most of the tweaks for Spi hurt pifast... ram helps, but it has to be an almost absolutely perfect balance of timings, including those retarded no-name subtimings..
quit working on the why's and who's of pifast since rick rolled me up and smoked me on Spi 8m, but if I can get close enough, I will be back on it and raping it once again...
*hint hint... how big is your screen? try different sizes for pifast.