You have to set your FSB @ 225 for RAM @ 1800.
Set RAM speed, timings and voltage manually(check RAM sticker).
Bumping up the FSB will overclock your CPU, CPU/NB and HT Link too Edited by IOSEFINI - 3/28/11 at 7:09am
post a pic with BIOS - voltages(same screen - scroll down)
keep HT Link freq around 2000 --> 2025
CPU/NB freq --> higher --> 2700
set NB voltage back to NORMAL, you need to increase CPU/NB voltage
Prime95 not AOD stability