memory not showing full spec

[mikep6t]

i have a asus p6t deluxe board with six gig of mem.but it only shows four gig. i have reinstalled the memory flashed the bios but still no luck can someone help please.

 

[mikep6t]

i have vista 64 bit system. on the bios it says 4 gb and on system 4gb

 

[mikep6t]

thanks will get on the case.