Why show different amount of RAM??

[exceeda88]

hello, i have a little problem..
i have one 1Gb RAM 800Mhz 5-5-5-18 and another 2 Gb RAM 800Mhz 5-5-5-18, both from kingston.
i already put both on master channel on my motherboard which use dual channel...
but why when i check on my computer properties it only shows 2040Mb. when i check with directx diagnostic tools also shows only 2Gb, but only when i check using cpuz it shows 3Gb RAM.
why is that??
im using windows vista ultimate 32 bit..


abit ax78
AMD x2 4800+
Power Color Ati HD3650 512 DDR3
windows vista ultimate 32 bit

 

[TheViper]

Run memory tests (accessible from Safe Mode or from other software; Everst).

Swap positions of the sticks and test.
Remove them 1 at a time testing them each individually.


Report back.