Text varies in size with image resolution

Hello why does the text size vary with res when pict is always say 1600x1200 on my mac
yet it does not vary on the pc it seems to compensate for change of reso fig
Ihave PS CS on both machines
john

I got the answer and other folk will meet same problem so here we are
I found that the mac PS was set to def points font size This seems to be a stricct math fig and only refs to screen display at 72 ppi
Now the pc was set to pix as font size now this is a fig that relates to the pix value of the pict displayed therefore it adjusts to whats displayed .Net result if you set fonts in pix the font size as you see it on screen follows the res and size of pict displayed.
Its the graphics kings who want points as they want books to come out at right size and printer does what they see on screen.
any how i think im about right as i understand it.All i have to do to be happy is set both mac and pc to read font size in pix not points.
cheers all i hope this helps some one out there John