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.

Index The Test


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  • tk109 - Monday, April 10, 2006 - link

    So they basicly have no answer to Conroe... Reply
  • rqle - Monday, April 10, 2006 - link

    yes we do, we still have that "previous generation vs. new generation" quote we can always used. LOL. just like AMD64 vs northwood/presscott.

    But really though, i assume the amd crowd should be a little smarter and get over that quote.
  • phaxmohdem - Monday, April 10, 2006 - link

    I get a bit confused as to what generation is what, and where you draw the line at a generation change for instance:

    AMD -> Intel

    486 -> 486 <--Gen 4
    K5/K6 -> Pentium <--Gen 5/6 vs. Gen 5
    K6-2/3 -> Pentium II <-- Gen 6
    K7 Athlon -> Pentium III <--Gen 7 vs. Gen 6?
    K7 Athlon XP -> Pentium 4 Willamette/Northwood <--Gen 7
    K8 A64 -> Pentium 4 Prescott <-- Gen 8 vs. Gen 8??
    K8 A64 -> Conroe/Core <-- Gen 8 vs. Gen 9?

    Perhaps someone can shed some light on this.
  • Shintai - Monday, April 10, 2006 - link

    How did Prescott become Gen 8? Its a northwood with 64bit

    Conroe is Gen 8. So your table should say K8 (Gen8) vs Conroe (Gen8)
  • Furen - Monday, April 10, 2006 - link

    LOL, how do you define a "generation"? What kind of changes indicate that you're talking about a new generation? The K8 is remarkably similar to a K7, so is it a newer generation or just an improvement on the same one? Does it even matter?

    The K8 has been on the market for close to three years now, so it's completely understandable that a brand new architecture will give it a run for its money. I'll say this, though, both the K8 and the Prescott came out at around the same time, so considering both the same generation is reasonable.

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