Corsair XMS2 4GB PC6400 DDR2
will the Corsair XMS2 4GB PC6400 DDR2 work with Asus p5n-D motherboard?
No, you need to put a pair of 2GB modules in to get 4GBs, not a single 4GB. Putting in a pair would enable the dual channel mode of the board and save money. Plus, your motherboard only supports up to 2GB modules.
Easy to look up the specs of your computer yourself at the Asus website:
And you can download a copy of your manual, which is how I found the info.
And the Corsair site will tell you which of their products is compatible with your motherboard:
From this list at Corsair, I highly recommend 1.8V RAM