if the ebay link would work but your board is capable of faster memory, PC3200 as crucial suggests. I have had experince with Asus boards and find them to be picky when it comnes to memory although only with the high quality stuff.
The difference between high density and low density is usually referred to as buffered and unbuffered, high density is buffered so I doubt again the ebay memory would work.
Have a look here click here
it should explain things a little more clearly.