Final Words

If AMD's Socket-AM2 only offers a minimal performance increase, then why on Earth is AMD moving to it?

AMD has done a tremendous job of making DDR-400 last with their architecture. When Intel first talked about moving to DDR2 there was concern that AMD's delayed move to the new memory technology would result in it being behind the curve, but the absolute opposite held true; Intel showed no benefit from DDR2 initially and AMD did just fine with only DDR-400.

However times are changing, and after a very long hiatus Intel will soon resume increases in FSB frequency, not to mention that their new Core architecture is considerably more data hungry than anything we've seen to date. So on the Intel side of the fence, the greater bandwidth offered by DDR2 will finally have a real use. With Intel DDR2 demand increasing and more manufacturing shifting away from DDR, it now makes sense for AMD to jump on the DDR2 bandwagon as well. If AMD does it early enough, the transition to DDR2 will be complete before any of its products desperately need it, which is always a better route.

It's not the most convincing reason to switch to DDR2 today, but AMD has stayed on DDR1 far longer than anyone expected and it's better to be early than never. The fact of the matter is that CPUs will get more cores, reach higher clock speeds and feature more data-hungry architectural changes, all of which require more memory bandwidth. AMD's options are to either add more memory bus pins to the already staggering 939-pin package, or to embrace a higher bandwidth (and lower voltage) memory standard; the option it chose makes a lot of sense.

There's also this issue of efficiency; based on our ScienceMark results, AMD was able to build an extremely efficient DDR-400 memory controller into their processors. The Rev E processors are able to deliver over 5GB/s of memory bandwidth, which is extremely close to the 6.4GB/s theoretical maximum offered by a 128-bit DDR-400 memory interface. The Rev F AM2 processors we've tested aren't able to break 7GB/s yet, which albeit an increase of 35% over the best Socket-939 numbers we've seen, still ends up being only 53% of the peak bandwidth offered by a 128-bit DDR2-800 memory controller compared to the almost 80% we saw on the Rev E.

If we use history as our predictor of the future, it may take a few more revisions of AM2 before we see that sort of efficiency, if we ever do. AMD has come a very long way since the performance we saw back in January, and if that's any indication we may just end up seeing better performance out of Rev G and H processors in the future. The verdict is also not out on Rev F; although the launch is only two months away, we keep on hearing that availability won't be until July. While that's not enough time for AMD to be making major changes to the silicon, it is quite possible that the changes have already been made and they're just waiting to get new chips back from the fab.

Based on what we saw with the Rev E cores and DDR-500, coupled with our results here with DDR2-800, it looks like Socket-AM2 will offer minor performance gains across the board if paired with very low latency DDR2-800, but otherwise it looks like it'll offer performance as good as Socket-939. If you're looking for numbers, with DDR2-800 at 3-3-3 we'd expect to see 2 - 7% gains across the board, with the 7% figure being reserved for applications like Quake 4 or DivX and the 2% figure being far more common.

Why would you move to Socket-AM2? If you're well invested in an up-to-date Socket-939 system, and if these numbers we've seen here today hold true for shipping AM2 platforms, then there's no reason to upgrade immediately. However, if you're buying or building a brand new system, then by all means AM2 makes a lot more sense than Socket-939. Like it or not, DDR2 is the future, and AM2 will be the new socket for AMD's future 65nm parts as well. DDR2 is also competitively priced with DDR memory while generally offering higher bandwidths, and with most manufacturers transitioning to DDR2 now we expect to see further DDR2 price cuts.

With AM2 you are investing in memory that will have a longer lifespan and a motherboard that will have a better upgrade path than Socket-939 today. The only other advantage other than a more secure upgrade path that AM2 offers is AMD's upcoming Energy Efficient desktop CPUs. We're particularly intrigued by the 35W Athlon 64 X2 3800+; if you thought AMD's processors were cool and quiet, a 35W X2 should blow you away. (It might overclock really nicely as well!)

The disheartening news for AMD and its fans alike is that if AM2 can't offer significant performance increases over what we have now, then all Intel has to do is execute Conroe on schedule, delivering the performance we've been promised and 2006 will be painted blue. AMD has been telling us that 2007 is the year we'll see major architectural changes to their processors, so AM2 may very well be as good as it gets for now. That's still very good, of course - the fastest X2 chips still outperform the fastest Pentium D chips - but it looks like after three years K8 may finally get some competition for the performance crown.

Does AM2's Performance Make Sense?


View All Comments

  • AdamK47 3DS - Monday, April 10, 2006 - link

    Conroe WILL perform better than AM2 no matter how much spin people try to put on it. Reply
  • bob661 - Monday, April 10, 2006 - link


    Conroe WILL perform better than AM2 no matter how much spin people try to put on it.
    How can you say this when there are exactly NO shipping Conroe parts? I THINK that Conroe will be competitive but even that opinion is speculation at best. YOU won't know shit about Conroe until it shows up at Newegg!
  • Shintai - Monday, April 10, 2006 - link

    If your logic applies, then he wont know anything about Conroe until he got it at home and working. So get over it, even the ES samples out in the wild kicks AMD so hard. The only question was if AM2 would bring extra performance to compete against Conroe, and it surely didn´t. Conroe prices also leaves AMD in the utter dust along with performance. 300$ Conroe E6600 chip or a 1200$ FX62? And the E6600 will be faster in most situations. You gotta be some extreme hardcore fanboi not to go Conroe. Reply
  • bob661 - Monday, April 10, 2006 - link


    So get over it,
    There's nothing to get over, asswipe. You nor he knows for sure how Conroe performs, period! You can fanboi me all you want. Facts are facts. When they ship and there are 3rd party benchmarks on 3rd party machines tested, then we'll all know for sure how they'll perform. Puff, puff, pass man, puff, puff pass.
  • Shintai - Monday, April 10, 2006 - link">">">">

    Now cry me a river again and keep whining over something new.
  • AnnonymousCoward - Monday, April 10, 2006 - link

    That's the crappiest website ever! I think a modem is hosting it. Plus it's retarded how the pictures shrink after they're loaded. Reply
  • Furen - Monday, April 10, 2006 - link

    I wouldn't compare the pricing quite yet. AMD's AM2 pricing is for May 5th while Conroe's is for launch day... whenever that happens (and before you say June/July, Intel itself said that it would launch as close to the beginning of Q3 as possible but did not commit to an early Q3 launch).

    Another thing, I have yet to see an E6600 being tested in "most situations", so until I see so, I'll say that your assumption that this is true is a bit irresponsible and fanboyish. Especially so if you consider that neither of the two CPUs (AM2 K8s and Conroes) can be bought quite yet, so convincing someone that one is a better deal is a bit premature. Personally, I think that AMD is going to get its ass handed to it by Conroe but I wouldn't go our of my way to swear it.
  • redbone75 - Monday, April 10, 2006 - link

    Wow. Only twenty posts until someone put up something about Conroe performance. In case you haven't been reading AM2 news or even read the article, AM2 is supposed to launch in June and here we are in April with a preview that, for the most part, is pretty disappointing for anyone that had high hopes for a Conroe challenger. This is just like when Intel migrated to DDR2: it wasn't really necessary but it will give AMD experience for when they can really use it. However, I'm thinking it won't take AMD as long to see more noticeable performance gains with DDR2 than Intel. Regarding Conroe, any way you call it the chip is going to kick some serious @$$, especially if Intel doesn't have any problems ramping up the clock speed. Also, Conroe is still several months away, so unlike AMD, Intel still has some time to tweak the chip for even more performance for its scheduled launch time (won't say date because there is none yet), so who is to say that the current performance claims are bogus. Even if they are now, which I seriously doubt, there just might be enough time for Intel to live up to the hype anyway. Reply
  • MrKaz - Monday, April 10, 2006 - link

    I'm not sure,
    but I think anandtech tested it at 533Mhz again, or
    the processor is locked at 533Mhz.

    Why did anandtech do the test only at 800Mhz?
    Why didn’t test 533Mhz and 667Mhz DDR2 modules?

    Because looking at those numbers:
    -DDR2 533 will achive less bandwidth than DDR400?
    -The latency of DDR2 is lower than DDR1?!?!
    -Is the processor already full, so doesn’t need more bandwidth, and only at (theorical) 4GHz and beyond will use it?
  • defter - Monday, April 10, 2006 - link


    The latency of DDR2 is lower than DDR1?!?!

    At higher speeds yes. Of course 3-4-3 @ 400MHz (DDR2-800) will offer lower latency than 2-2-2 @ 200MHz (DDR1-400).

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