how to find out the ram which is compatible with my intel 845G motherboard?
 

I am using intel 845G motherboard(2 GHz). On my ram, DDR333 is written, what does that mean? does that mean DDR1, DDR2 or DDR3?? i want to buy a new ram. which ram would be compatible for my motherboard. and what are the other factors that i have to look into while buying a ram???