OK assuming that you have the 95 Watt version of the CPU then the first thing I would do is reflash BIOS using the QFlash Utility, just to make sure that there isn't an issue there.
When you reflash the BIOS make sure you disable the "Keep DMI Data" Option on the QFlash homescreen before actually running the programme. This will make sure that the old settings are overwritten and will give a clean starting point. When you have completed the reflash go into BIOS and load Optimised Defaults then reboot and let the system start. Is the CPU still showing as only running at 800MHz?
Could you clarify your RAM and how much you are running is it 3 sticks of 2Gb's to give the 6 GB total?