That is odd, regardless of the resolution. With your processor, no resolution should cause any lagging, especially with a program that should run fine at *half* your processor's capabilities. Whatever the problem may be, I might venture a guess that it relates to your computer's inability to properly enter fullscreen in pSX. Fixing one problem will probably fix all three of them. I'm just hoping somebody comes along with more knowledge than me in this area, as I know almost nothing about Macs.
My best answer to you would be to go to the
official forums and ask there. If you're lucky, pSX Author himself may see your problem and possibly have an answer. And if not, there are many regulars besides myself, and many of them would probably be more helpful than me...
