memory - How much ram does my pc has?

I want to turn this old pc into a home server.

When I bought it (few USD) I was told it has 4 GB ram but I only see 3072MB

The SPD says slot0 2048 and slot1 2048 but DIMM says 2048 and 1024.

So does it has 3 GB of ram ? on livecd it shows 3 gb as well

Update

 description: Motherboard
       product: P5KPL-AM SE
*-firmware
      description: BIOS
      vendor: American Megatrends Inc.
      physical id: 0
      version: 0702
 *-memory
      description: System Memory
      physical id: 23
      slot: System board or motherboard
      size: 3GiB
    *-bank:0
         description: DIMM DDR2 Synchronous 800 MHz (1,2 ns)
         product: PartNum0
         vendor: Manufacturer0
         physical id: 0
         serial: SerNum0
         slot: DIMM A1
         size: 2GiB
         width: 64 bits
         clock: 800MHz (1.2ns)
    *-bank:1
         description: DIMM DDR2 Synchronous 800 MHz (1,2 ns)
         product: PartNum1
         vendor: Manufacturer1
         physical id: 1
         serial: SerNum1
         slot: DIMM B1
         size: 1GiB
         width: 64 bits
         clock: 800MHz (1.2ns)