Ok, so your memory sticks should be compatible with your mobo. Have you tried my previous suggestions? You can also move the sticks around (place the sticks of your CORSAIR set into different slots), and see if that fixes things.
Try placing them in the second slots...works better. If not, a Bios update is in order...
Any updates telnet05? I also realized that CPU-Z may not see your extra 2GB because you might running on a 32-bit OS like Windows. Could be wrong though.
put the rams in the white stick you should left up the voltage