I've been following computers for a long time except the past year or so cause of occupation and being busy. A friend recently asked me to build a computer, and right now DDR 3 is pretty expensive, and there's a lot of different types of DDR3, I was aiming for a Maximus board since it allows DDR3 but I'm wondering if I'm able to put DDR2 in it for the time being and buy DDR3 later on? And what the big difference between all the DDR3 is... thanks!

DDR3 is basically the 3 step in DDR-SDRAM technology. DDR1 took us to 200MHz (DDR400) @ 2.5v, DDR2 takes us to 533MHz (DDR2-1066) @ 1.8v, DDR3 will take us to 800MHz (DDR3-1600) @ 1.5v. Those are the official JEDEC (Joint Electron Device Engineering Council) standards. You will see higher rated RAM...DDR500 or DDR2-1200 for example, but they don't conform to the JEDEC standard because there's no spec to conform to. In most cases, they're just standard JEDEC RAM that is overclocked, overvolted & have heatspreaders installed. There's currently little advantage to running DDR3. The performance benefits are minimal & the costs are higher than DDR2. DDR3 can NOT be run in DDR2 RAM slots & vice-versa, although there are *some* boards that provide both DDR2 & DDR3 memory slots. If you insist on building a system that uses DDR3 RAM, check this recent review: Mainstream-Ready? DDR3-1600 Shootout "If my answers frighten you then you should cease asking scary questions" - Jules Winnfield (Samuel L. Jackson) in Pulp Fiction

way to go Jam!!!you hit it right on the button