You *should* be able to. The computer will just use the speed of the slower RAM. I haven't tried it myself, though. -- Rich On Thu, Jan 15, 2009 at 1:53 PM, Dan A. Currie <dancurr at frontiernet.net> wrote: > Hello All, > > Can you mix PC2600U-25330 DDR Ram with PC3200 DDR Ram on an MDD 1.25 dualie?