i'm absolutely sure they are all 64x. the only computers i have running 32 bit are the main htpc with xp and a couple of laptops.
weird thing is though that it is reporting different amounts on different computers. maybe i'll switch out a harddrive and do a fresh win7 install and see what it says.
i figured it out.
i had checked the "maximum memory" box in the msconfig - boot tab - advanced window and it was limiting the amount of usable ram i had available. all fixed now.