I’m having some trouble with the memory detection on my system, and I need some help.

I have trawled the net in search of a resolution and I have tried various things listed below.
Unfortunately they have had no effect, so I’m looking for some suggestions, I do however have a feeling that the motherboard could be faulty.

I am also encountering the problem with the CPU temperature reporting only sometimes working.

Problem
Bios and windows only seeing 2GB of the 3GB of memory.
CPU-Z sees all 3 sticks of memory.
System installed without problem and runs fine even though some memory is not detected
Each memory stick passes memtest OK individually

i haven't encountered this before, i've tried to flash to the latest 1005 bios, but it seems not working too..

any idea..?