Asus P5WDH Deluxe and 4gbs of ram

I have the asus p5w dh deluxe board. I have 4 x 1gb sticks of corsair ddr2 800 ram (all identical sticks.. same manufacture date.. etc.. all working tested in other computers). My problem is.. in the bios post it shows only 3gb (3072) and
in the operating systems (64bit) it shows 4gb.. but can only use 3gbs of it before it gets capped. I go into the bios and look and system information and it says "Total memory: 4096, total Available memory: 3072, Memory appropriated : 1024. (looked up appropriate, means to take for ones self... why is the mobo taking the 1gb of ram for itself?)

Does anyone know why i cant use that last gigabyte? thanks

in your bios go to memory remaping and enable it. that should give you 4gigs in windows if you have 64bit
Rich

that did the trick. Thanks

np thats what we are here for to help each other
Rich