P4P800 how picky was it about ram?

[Swampthing]

I just put one of these in an older computer and i can't remember if they were picky about ram or not. I tried downloading hte manual from asus but it's in chinese at all the links for it so i can't even see what they recommended. This person has 2 sticks of 512mb ddr400 and 2 sticks of 256 MB ddr400, think that'd pose a problem?