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Conclusion

Ok, that was a lot of work - and a lot of fun.

Clearly AMD has delivered a very viable processor with the AM2 launch. The on-board DDR2 memory controller provides extremely low DDR2 latency that cannot be matched even by the excellent Intel 975X chipset. Some might consider that AMD took their sweet time to release a DDR2 capable platform, but AMD would argue that Intel was prematurely forcing DDR2 down people's throats before the technology was mature enough and prices stable enough for consumers.

AMD's AM2 launch comes at an opportune time: PC2-6400 DIMMs are prevalent and accessible price-wise, and high performance, low latency DDR2 is already becoming more widely available. An earlier launch would have been in a climate where DDR2-5400 was the norm, which would likely have performed slightly worse than low-latency DDR-400 - something I intend to test soon.

I also find it very impressive that AMD is launching a whole line of processors on the same day - the entire lineup we mentioned earlier is available as of today, encompassing everything from $67 value parts to $1031 monsters, for those that want the last possible ounce of performance. AMD tells us that the processors have been ramping for a while and availability and yields are good. What this means for consumers is that if you want AM2, you can get AM2, provided your retail store decides to stock the models that you want.

However, one of the nagging questions some of you may be wondering relates more to AM2 performance versus existing Socket 939 equivalents. Does socket AM2 blow away socket 939?

Not by a long shot.

Yes, it can provide higher memory bandwidth, but as you can see from our charts, there is little practical difference in the performance of identically clocked DDR- and DDR2-based processors in anything except raw memory benchmarks. Most of our real world tests showed the 939 and AM2 versions of the X2 3800+ performing with almost no measurable difference and I expect this to be representative of a clock by clock comparison of the AM2 and 939 processor lineups.

Am I going to toss out my existing DDR-based Athlon 64 systems? Nope -- and neither should you. If you already have an existing 939 platform and intend to do an incremental upgrade -- say from a 3400+ to a 4400+ -- you can stay with the 939 platform knowing you didn't miss out on additional performance.

Will I start to purchase AM2 based systems? Yes - if the total price is equivalent to DDR based systems, or if I'm building a new system with upgradability in mind. AMD has made a commitment to provide 939 chips as long as there is demand for them, but with higher end parts in the AM2 platform, and with overall lower power consumption and especially the Energy Efficient AM2 processors, I think many new builds will be incorporating AM2.

You might have also noticed that our stock AM2 5000+ was performing neck-and-neck against the 939 FX-60 -- the former glory boy of AMD. With the FX-62 taking the crown, the 5000+ becomes a very logical choice for the high end gamers trying to mix performance with some price savings.

AMD also chose this opportunity to fine-tune their power consumption. Certainly the Athlon and Sempron AM2 families represent the highest-efficiency 90 nm CPUs that we have seen to date, putting Intel's power-hogging Prescott-derivatives to shame. Our 5000+ consumes 89W TDP, the same as a lower-clocked X2 3800+ 939 model, and less than both a 110W 939 4400+/4800+ and the whopping 130W of an Intel Pentium D 840 (which is still a 90nm process chip).

That's a significant difference and is sure to affect your overall system power, heat, and overclocking headroom (not to mention a small effect on your electrical bill). Our significant overclock of the 5000+ from 2.6 GHz to 3.0 GHz using the early review sample is just a taste of just how much headroom even the highest-clocked member of the AM2 family has. The lower power consumption also leads to a lower heat output. We used both a stock AM2 cooler and also a Zalman CNPS-9500 AM2 cooler, and temperatures after loading Windows were hovering at an amazing 38 degrees Celsius! Even overclocked load temps don't breach 60'C under air cooling, staying at or under 59'C during all our tests.

The bottom line with the AM2 is that AMD has achieved an amazingly low-latency DDR2 memory controller and moved its platform into the mature DDR2 space. If nothing else, that step is critical to AMD's continued ramping up of performance. Coupled with lower power consumption and the resultant excellent headroom and yields means that AM2 has a lot looking out for it.