This motherboard does not support 1066MHz RAM and also the CPU you are running may not as well. It isnt worth putting 1066MHz ram in as it will only run at 800MHz
The motherboard does support 4GB or RAM for 32 bit operating systems
and 8GB for 64 Bit operating systems.
also if you decide to upgrade your CPU make sure it isn't over 89 watts as the mobo wont support it.
http://h10025.www1.hp.com/ewfrf/wc/d...roduct=3397528