DDR2 vs DDR3

I'm building my first gaming computer, and though it took me a while, I got what seemed to be a fairly good setup. However I don't receive all the money I will be using for the computer until a month from this date, so I'm attempting at borrowing parts. Which would result in the possibility of my using DDR2 rather than DDR3.

The main problem was in a motherboard that supported the Phenom II X4 BE that was in a reasonable price range (ultimately the cheapest), so I chose this one.
http://www.newegg.com/Product/Prod [...] -_-Product

However, I was wondering what the difference between DDR2 and DDR3 is, as I was thinking about getting this instead, because of the combo with the power supply I wanted:
http://www.newegg.com/Product/Prod [...] 6813138168

I suppose I had a laced, second question, about whether or not those mobos wouldn't work well enough for my processor and video card:
http://www.newegg.com/Product/Prod [...] -_-Product
But that's probably irrelevant.
Thanks for any replies.

well the difference is speed, which dd3 are clocked higher so will have higher memory bandwidth, and ddr3 uses less power i believe, in real word apps doens't make too much of a difference, unless your using a program that relies heavily memory, so if you can save a pretty significant amount of money then it's no problem

and for your 2nd question, yes both will work for you cpu

no not really your mobo really determines how man expansion slots at your disoposal and other connectivity options, such as usb 3.0 sata 6gb/s, firewire,

so if your going with a single card you'll be fine, because it'll be at x16. now if you want to CF or SLi then your mobo matters. the only other thing that would potentially effect performance, is cpu overclocking potentail, but it's really a marginal thing, a super high end mobo might allow you an extra 5% overclock

You could try running at tighter timings than advertised. Actually nab CPU-z and it will tell you what the timings are for each speed. And really 1600 RAM isn't really needed. The 1333 is usually a good place to be. I mean, you can return it but then if it's your mobo being the problem you'd just have to buy something else.

only at 809mhz do the timings change from 9-8 on the first three numbers.
2 things I noticed though
1. it says I'm running at 667mhz, and I could go to 800mhz and that would qualify as "XMP-1600"? I'm a total newb, sorry.

and 2. It prevails that my fsbram is 1:4? I do remember something about 1:1 and how it would boost your system. If so, how could I find out about doing it?

Do you know why it would receive only a 5.9 in windows 7 experience rating, though? On newegg, others received a 7.1 with the same product. Do I just need to change out my motherboard?