Ram not registering

Hi, i just built a new computer
EX58-UD4P m/b
G-B 9800gt 1g v/c
3x2g kingston 1333mhz ram
Core i-7 920 CPU

My problem is that not all my ram sticks are registering on windows vista, showing 3.25g ram instead of 6g, however when i run belarc advisor, it shows all 3 ram sticks installed.

Does anyone know what the problem is?

It sounds like you have the 32-bit version of Vista.

32-bit Windows has a MEMORY SPACE of 4GB (4096MB). This space includes the System RAM, some motherboard components and add-on cards (a video card with 512MB of Video RAM will use just over 512MB of that space).

I just noticed you have a 1GB video card which implies that you have Vista 64-bit so now I'm not sure what to think.

It's possible that you are reading the amount of RAM incorrectly. You should:

1) Download and run Memtest (USB, floppy or CD). It will show you how much RAM your system detects.

2) Open the Task Manager (CTRL-ALT-DEL), the amount of RAM you have should be under "Performance"-> "Total"; yours should read about 6144MB or just under.