Originally Posted by tipsycoma
Not much difference between DDR2 and DDR3. In gaming, you won't notice a bit of a difference. I say DDR2, it will save you some money that you could put towards a better GPU or something of that sort.
Well let's not jump to conclusions with that; the first question from us should be "what motherboard are you using?"
It depends on your motherboard! If your motherboard is a AM3 only motherboard, you NEED to buy DDR3. If it supports AM2/AM2+ platforms, then you NEED to buy DDR2 (I've only seen one mobo support both, so I will assume you don't have that model).
Please go to your user control panel and find the "Add System" link to fill in your system specs. This will enable all of us here to help you better