Do you already have 1 module? You should try to ahve two of them to run in dual channel, a little 3-5% but still ebtter than nothing!
Geil is good stuff I dont knwo about Kingmax.
Try to find some OCZ value VX this is good stuff, otherwise just stick with known manufacturer.
Asus P4P800DX, P4C firstname.lastname@example.org, 2X512 OCZ PC4000 3-4-4-8, MSI 6800Ultra stock, 2X30gig Raid0