What's AM2?
As we've mentioned before, AMD's Socket-AM2 is a brand new 940-pin socket that will add DDR2 support for all desktop AMD processors. There will be AM2 versions of Athlon 64, Athlon 64 X2 and Sempron CPUs. All of these are internally known as the Rev F core. When AM2 launches in June, AMD will offer official support for DDR2-533, 667 and 800. As of today, the fastest DDR2 that Intel officially supports is DDR2-667; however, by the time Conroe launches in Q3, Intel will also add DDR2-800 to the list.
What this means is that if you're planning to build a new system later this year - whether it is AMD or Intel based - then you'll be in the market for DDR2 memory. AMD has effectively kept regular DDR-400 quite alive and actually created a market for even faster DDR1 memories with their Athlon 64, but after June that's all going to change. With a single memory standard to support both players in the desktop market, things are going to get a lot simpler. It will also mean that we'll start to see more focus from memory vendors on DDR2, including cheaper variants as well as even lower latency offerings. We'll address whether nor not DDR2-800 is actually needed shortly, but like it or not, if you want a solid upgrade path for the future you'll be looking at investing in some DDR2 memory regardless of whether you choose AMD or Intel.
Alongside DDR2 support, the new Socket-AM2 CPUs add support for AMD's Pacifica Virtualization technology - AMD's answer to Intel's VT. While the two technologies aren't directly compatible, given the respect that AMD has gained over the past few years you can expect software developers to support it. Virtualization will become increasingly more important as time goes on, as we have already seen in recent announcements of Intel VT support on Apple platforms.
The third thing that AM2 brings us is what AMD is calling their Energy Efficient microprocessors. Certain SKUs of AM2 processors will be binned according to their power consumption and grouped into two categories: 65W and 35W. Both TDPs, interestingly enough, are competitive with what Intel is targeting for their 65nm Conroe processors. What's even more impressive is that there will be an Athlon 64 X2 3800+ that's available at both 65W and 35W TDPs, compared to the standard 89W TDP. The chart below will give you an idea of what the new dual core AM2 CPUs are:
| CPU | Clock Speed | L2 Cache Size | TDP Options |
| AMD Athlon 64 FX-62 | 2.8GHz | 1MBx2 | 125W |
| AMD Athlon 64 FX-60 | 2.6GHz | 1MBx2 | 125W |
| AMD Athlon 64 X2 5000+ | 2.6GHz | 512KBx2 | 89W |
| AMD Athlon 64 X2 4800+ | 2.4GHz | 1MBx2 | 89W or 65W |
| AMD Athlon 64 X2 4600+ | 2.4GHz | 512KBx2 | 89W or 65W |
| AMD Athlon 64 X2 4400+ | 2.2GHz | 1MBx2 | 89W or 65W |
| AMD Athlon 64 X2 4200+ | 2.2GHz | 512KBx2 | 89W or 65W |
| AMD Athlon 64 X2 4000+ | 2.0GHz | 1MBx2 | 89W or 65W |
| AMD Athlon 64 X2 3800+ | 2.0GHz | 512KBx2 | 89W or 65W or 35W |
In the future you can also expect an FX-64 along with 5200+ and 5400+, but the chart above is what will be launching in the near future (the exception being that the 65W 4800+ that will launch in Q3).
There will also be single core Athlon 64 and Sempron AM2 processors, but we're still waiting for their confirmed specs. Given the specs of the Athlon 64 X2s, you can expect the AM2 Athlon 64s and Semprons to be identical to their Socket-939 counterparts. We'll also finally get retail availability of faster Sempron parts - current socket-939 Semprons are only available with OEM systems.
AMD has already indicated that it will not brand the 65W and 35W parts any differently than the normal 89W Athlon 64 X2s; they will simply have a different part number and carry some sort of lower TDP designation on their box. Of course, they will almost certainly carry a price premium, so that at least should help to differentiate the models somewhat.
As far as major architectural changes go, we haven't been able to find any surprises in any of our AM2 samples. L1 and L2 cache latencies remain unchanged from their Socket-939 counterparts.
You will also notice that AM2 and Socket-939 CPUs appear to carry the same model numbers, meaning that an AM2 X2 4800+ runs at the same speed and has the same cache size as a Socket-939 X2 4800+. Either AMD is being very conservative with its model numbers or we shouldn't expect to see any major clock-for-clock increase in performance with AM2 processors.
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savantu - Monday, April 10, 2006 - link
Anand , please correct the values in the table at the Adobe and multitasking tests , they should be negative.savantu - Monday, April 10, 2006 - link
..It's time so less is better.Anemone - Monday, April 10, 2006 - link
Don't forget capacity. If you loaded up 4 memory slots to bring 939 machines to 4gb, you harmed timings. DDR2 can bring 2gb on a module at good timings and thus make a higher performance 4gb machine. Why is this important? In Vista (yep I know it's delayed) you will find that gamers and power users of a wide variety will want 4gb machines, much the same as a good number of folks are starting to use 2gb machines now. The larger footprint of Vista ups the ante. It's not that 2gb won't be enough, it will do. Just as 1gb today "will do". But come the end of this year 4gb will start to be that cutting edge amount and that suits the use if DDR2 very well.You already mentioned the power issue, with 1.8V for DDR2. That is something AMD needed in the mobile arena to stay competitive, so if they were already designing a top notch DDR2 controller, might as well do the entire cpu line. Since much of the market is actually starting to shift to mobile solutions, from a growth standpoint, being competitive here is going to be telling in each company's numbers. Since Merom is having heat issues (hence why Conroe is coming out so far ahead of Merom, meaning less of a heat budget constraint) you can expect that Turion X2's with DDR2 will put some pain on Yonah machines. I suspect that AMD knows their bandwidth is superb with DDR2 and are designing Turion X2's with 512 cache because it doesn't hurt them much. Watch this area in 2006, because the world won't be painted blue if AMD does well here. Intel is likely well aware and will push as hard as possible to bring Merom out to keep AMD from making ground. Mobile designs under S1 socket are coming aplenty.
$.02
coldpower27 - Monday, April 10, 2006 - link
I must have missed it by what clock rate and what amount of cach were the models used???
Anand Lal Shimpi - Monday, April 10, 2006 - link
We purposefully didn't publish this information to protect our source of the CPU.Take care,
Anand
flyck - Monday, April 10, 2006 - link
well ofcourse we don't know the clock. But it is an important factor. @ 1.8GHz A64 didn't bennifit from dual channel. but it think @ 2.8GHz that story was totally different. So if you are testing @ 2.4GHz. there could be a larger gap @ 3GHz for example.Anand Lal Shimpi - Monday, April 10, 2006 - link
Very true, but from what I've seen the picture doesn't change much from the 3800+ up to the FX-62, at least with current CPUs/platforms. The main thing that shows a performance difference is when going to even lower latency memory. You are right though, the hungrier the CPU gets (faster clock, wider core, etc...) the more it depends on a high bandwidth memory bus. However, I do believe that AMD's own model numbers tell the tale of what to expect.I think that at the end of the day the 2 - 7% increase range is what will hold, with the vast majority of applications falling at the 2% end of the spectrum.
Take care,
Anand
ozzimark - Monday, April 10, 2006 - link
though one thing to keep in mind: memory efficiency is directly related to the cpu mhz. i've found that going from 2ghz to 3ghz while keeping the ram at 250mhz increases bandwidth by around 1800mb/s on my s939 rig :eek:Sunrise089 - Monday, April 10, 2006 - link
I think there will be a lot of current users taking the upgrade path in my subject line, or something close to it. I may very well buy a new AMD chip in 2007, I'd sure like to be able to, but for the next 12 months I only see myself buying a used, overclock proven 2x1meg cache s939 X2 at the end of summer, and then trading up to Conroe during the holidays. I can't really see anyone but the strongest fanboys (and I'm pretty strong) buying AM2.AnnonymousCoward - Monday, April 10, 2006 - link
Why in the world do you upgrade so often? My path might be AthlonXP 1800+ --> Conroe.