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  • Nemesis77 - Monday, April 26, 2004 - link

    "The FX51 is dual channel but in those recent AT tests it was virtually the same as the a64 in performance even in bandwidth tests like encoding"

    You need to keep in mind that Opteron/FX uses registered DIMM's, and those carry a latency-penalty. Socket939 gets the benefit of increased memory-bandwidth without the drawback of increased latency (like Opteron/FX does).
  • Pumpkinierre - Saturday, April 17, 2004 - link

    Yeah the performance difference between the dual channel and the single channel as well as the P4 is a mystery. The FX51 is dual channel but in those recent AT tests it was virtually the same as the a64 in performance even in bandwidth tests like encoding(http://www.anandtech.com/cpu/showdoc.html?i=2002&a... FX51 creams the P4 in synthetic bandwidth tests (sandra, sciencemark2) which is strange because the P4 is quad pumped. But that dominance doesnt seem to translate to the media streaming apps tests where the P4 still has the edge. The FX53 is competitive so cpu clockspeed might be more important than bus width which makes me think that the bandwidth tests are as much latency dependent as bandwidth dependent. Based on the AT encoding test, the single channel a64 is almost as good and is probably lower in latency and stabler. So there must be a bottleneck here, or dual channel come into its own with cpu speed increase (the FX53 points to this but a scaling test is needed), or AMD's twin channel is a big con and you dont need it.
  • Boozish - Saturday, April 17, 2004 - link

    making for very very little performance difference
  • Brickster - Saturday, April 17, 2004 - link

    To #14...

    Dual Channel memory support to all A64's also for 939.
  • Boozish - Saturday, April 17, 2004 - link

    Now that the Newcastles and 939-socket cpus are almost the same, i dont see the point of going from 754 to 939. The only thing that looks good about the 939 is the pci-express mobos.
  • AsiLuc - Saturday, April 17, 2004 - link

    I didn't know this.
    But, is it correct to assume that the Athlon 64 fx will still feature 1 mb cache? Does fx go from 940->939 with dualchannel and 1 mb?
  • KristopherKubicki - Friday, April 16, 2004 - link

    I hope i knew it, i mean, i wrote the last article too!

    the only real news here is the bump in clock speed.

    Kristopher
  • Jeff7181 - Friday, April 16, 2004 - link

    No offense to the author of the article... but... this is news??????? I thought we already knew this... I already knew this... did you?
  • KristopherKubicki - Friday, April 16, 2004 - link

    Trogdor: Thats IF you believe the PR ratings are really actual ratings and not just marketing labels -- :-X Not to be cynical or anything...

    Kristopher
  • TrogdorJW - Friday, April 16, 2004 - link

    Don't get confused by the socket 939 CPUs, people. Here at least we are getting some good benefit from Newcastle. We lose a few % points in performance from the decreased L2 cache and got up anywhere from 8 to 10% in clock speed. (Though perhaps we don't benefit as much as AMD - they just trimmed core size by about 30 million transistors, it looks like... almost 25% fewer transistors! They cut costs by at least 20%, price stays about the same. Don't see any Fanboyz trumpeting that, do you?)

    What bothers me is the 939 CPUs that will have the same characteristics as Newcastle, but get higher ratings due to the dual-channel RAM capability. I believe the 2.2 GHz 939 CPU is going to be a 3500+ and the 2.4 GHz 939 will be a 3800+. Maybe we really will see a >10% increase by going to dual-channel and socket 939, but the cores will still be virtually identical, won't they? Or maybe there are extra HyperTransport connections on 939 CPUs that add cost and transistor space?

    Oh, well. So we went from "Model 4" processors to "Model C" - what happened to models 5 through B? Hopefully they were just not as good as the new and improved Model C, right? Maybe overclocking might actually achieve greater than 10% bumps in performance now.
  • KristopherKubicki - Friday, April 16, 2004 - link

    mkruer: The PR rating doesnt change - they take away half the cache, and increase the clock by 200MHz.

    Kristopher
  • Pumpkinierre - Friday, April 16, 2004 - link

    The loss of cache would only matter if you're using the cpu for server use- the heritage of clawhammer from opteron (sledgehammer). The performance difference between the 3000+ and 3200+ was negligible. However clockspeed increase is more desirable as it improves alu and fpu as well as lowering the memory controller latency yet more. Unfortunately it doesnt do the same to system RAM but if the adjustable lower end multipliers are still there on Newcastle, lowering of the multiplier should allow an even bigger boost to the system memory speed and hence latency, than the lower speed clawhammer cores. Naturally good mobo and RAM are required.

  • mkruer - Friday, April 16, 2004 - link

    Hum something seems amiss. The core gets a revision looses ½ the cache and the PR rating goes down 200? I though the entire idea was for the core revision to cut the cache in ½ and keep the rating? Clock for clock wasn’t the Newcastle suppose to be faster?
  • Sudder - Friday, April 16, 2004 - link

    > and encoding may suffer.

    I don't think so, since encoding is very clock dependent - in fact I think anything in 32bit won't be a big problem.
    64bit however could be a different story, since the bigger variables need the double ammount of cache (512k Cache @ 64bit = ca. 256 Cache @ 32bit)

    Sudder
  • clemedia - Friday, April 16, 2004 - link

    Why do you say "the 50% smaller cache size has many negative implications; content creation and encoding may suffer."

    When in your Athlon64 3000+ article the 3000+ was only about 3% slower in CC and about 4% in encoding than the similarly clocked 3200+? I would think the 10% increase (2.0 -> 2.2) should be able to more than offset the perf. decrease.

    Can't please everybody all the time can ya? hehe.
  • PorBleemo - Friday, April 16, 2004 - link

    Well it can't be expanded. And if 64-Bit is really assisted by the additional 512Kb of cache (because of the need to trigger the extra registers) you can't add it back on easily. Beyond that I can't think of anything.

    -Por
  • Brickster - Friday, April 16, 2004 - link

    "the 50% smaller cache size has many negative implications."

    And those would be?

    Thanks,
    Brickster
  • PorBleemo - Friday, April 16, 2004 - link

    Another thing not mentioned is that Clawhammer has more effecient Cool N' Quiet because of less leaking.

    -Por

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