Can you replace DDR PC2700 with DDR2 PC4200?

[LuciniaFletcher]

Roomie has a p4 laptop with DDR PC2700 in and and I was going to buy her some more memory but DDR2 PC4200 is about $40 cheaper.

Is there any reason that memory won't work right? I remember reading somewhere that there was a voltage diffrence, but I can't seem to find the article.

 

[RobsTV]

No. DDR2 won't fit into DDR socket.

You can replace DDR PC2700 with DDR PC4200 (if you wanted to, and could find it).
There would be no gain in doing this though.

 

[phaxmohdem]

Alternatively, you can replace it with DDR3200 RAM as that is most likely cheaper than 2700. There will be no performance gains likely, but it is probably cheaper that way.