First off AM-2 is not necessarily better becuase it uses DDR-2 DDR-2 memory is faster but due to it's double latencies the speed improvement for the most part is negated by its substanial latencies.
The REAL reason for AM-2 is EXACTLY as you have just stated. Most PC buyers think DDR-2 must be faster because the spec numbers say so and its newer ! AMD made a decision when DDR-2 first became popular not to design CPU's for DDR-2 systems. AMD felt that DDR-2 was not all that is was hyped up to be and therefore paid it little mind. However they began to notice this marketing and engineering decision left Intel alone in the DDR-2 spec world; a decision they later came to regret. Intel being an advertising wizard began hyping the benfits of DDR-2 based systems. AMD had to play catch up and in a hurry at that, thus the release of AM-2 and to the benefit of those buying it; to slow down Intels progress in sales AMD is selling AM-2 processors at 939 prices or lower !!
Now on to overclocking:
Overclocking is primarily the hobby of extreme gamers and very computer committed enthusiast builders. Overclocking back in the Pentium days and even Pentium-2 days was a real big winner; you could get a huge boost from system perfromance back in those days because the system bottleneck WAS at the processor. Now days the data movement bottleneck is no longer at the processor but lies more at the hands of the 32bit bus. This will soon be fully addressed with the release of 64bit systems with 64bit software like Vista, however we will have to wait for 64bit software that is designed to make efficient use of the 64bit bus not just compatibility.
Now days the design of componets have been tweaked sooooooo tightly system overclocking is really a fad of past years. This statement will draw some rebuke from die hard overclocking fans; but I have heard it all before an they still have not convinced me or show me any substaniated proof of real noticible
improvements gained from overclocking. The biggest problem Overclockers face now with modern components is heat, and alot of it!!
Todays modern components produce insane heat, becuase they have been engineered to squeeze every last drop of perfromance out of them; they are in essence already overclocked!
To begin the overclocking endeavor takes a substanial additional investment, you will need a real kick a$$ power supply to achieve stable voltage manipulations, you will need high perfromance ram capable of sustaining very tight ram timings (check the prices on crucial ballastix and OCZ high perfromance memory) then you will need added cooling, most popular is water cooling due to its price and availability. Nitrogen cooling is the king of course but its difficult to set-up and insanely expensive.
Common overclocking steps are 5%, 10%, 20% and 30% 5% is very common and not to difficult to achieve with good ram, hot shot power supply and excellent air flow that can be achieved with case fans, the same is true with 10% stepping although it can be a tad tougher and now your getting into the mud.
20% is a core to achieve, now your into the land of perfection. To maintain a 20% overclock you will probally have to try several diff brands of high performance memory, not all ram sticks overclock well; not even the high perfromance models, not all motherboards will overclock well, I have seen motherboards that are the same exact models and one will achieve and hold 20% and the other wont !
For 20% overclocking you will need watercooling to maintain and run 20% continously especially when gaming. I have been told by extreme gamers that overclocking improves frame rates within gmaing enough to justify all this hassle, expense and RISK.
Its really a matter of preference, overclocking requires you to boost the voltage going to the CPU and ram beyond the manufacturer's stated spec. Some components are actually built to better specs right at the factory and can take a certain amount of this pushing. Some can not, the ones that can not often wind up burnt.
I have several friends that are avid gamers that have abandoned overclocking in favor of chasing better components when they become avaialble.
Its really a matter of personal preference whether or not to overclock, some motherboards are much better at overclockign than others. You will need to do alot of research prior to jumping in, there are a heap of excellent over clocking forums to research and chat with overclocking guru's. One thing is for sure about die hard overclockers, they demand all that a system will produice and they are willing to spend whatever it takes to achieve very modest gains. After all when you fry a $400.00 video card you damn well better be committed to what you are doing
I am sure we will get some other repsonse to the contrary.
goodluck and enjoy your research and adventure. Keep a sharp nose for that lovely burning smell; its your wallet on fire ROFL