Can you put a memory stick with a different frequency in the other slots. ie pc3200 or pc 2700?
*Yes, most PC3200 and PC2700 modules are backwards compatible and can run at PC2100 speed.
Also if you have a 256 mb stick in one slot can a 512 mb stick be put in the other slot?
*Yes, however, as a general rule of thumb its best if the largest module is installed in the first slot and any smaller modules installed in the remaining slots.
One last thing that interests me. I seen ddr 3200 184 pinn and just a few minutes ago i saw a ddr2 3200 204 pinn i believe. I was unaware that they made ddr2 ram at 3200 but now that I see they do how much better is the ddr2 stick actually going to be?
*DDR PC3200 modules are 184pin and operate at 2.5/2.6v. DDR2 PC3200 modules are 240pin and operate at 1.8v. Most likely the motherboard you have supports DDR memory only. DDR2 memory will not fit.
Hope this helps