More Cores, but where's the Elegance?

Architecturally, the two individual die that make up Kentsfield are treated as one. This distinction matters especially when you look at power consumption of the new processor. In the event that only one of the two die is being used, the other cannot simply power down; instead it has to run at the same voltage and frequency of the other active die. Within each die, the two cores have to run at the same frequency and voltage as well, so there's not really much flexibility in operation. The end result is that while Kentsfield doesn't use too much more power than Conroe when running four CPU intensive threads simultaneously given the additional work it is doing, when only running two threads, Kentsfield is quite wasteful with its power consumption.

A more efficient solution would be to allow each core to operate at its own frequency, and an even better implementation would require independent power planes per core - allowing for different voltages depending on load. As simple as these two options are to write, they are unfortunately far more difficult to implement. AMD has already announced that its Barcelona quad-core CPUs will support independent clock speeds per core, but not independent voltages.

AMD's Barcelona core, due out in Q2 '07, will have support for independent clocks per core but all sharing the same voltage

Index Using a Quad Core System
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  • JarredWalton - Thursday, November 2, 2006 - link

    I am quite sure that 4x4 is for 1207 and not AM2. Sorry. I am also quite sure that 1207 will get quad core support, so long-term a 4x4 (dual dual core) can become... 4x8? (dual quad core). Anyway, in that sense it's just like Core 2 Duo and Quad.

    The questions I don't have answers to: will the 4x4 begin with a K8L chip, or just a tweaked K8? Will K8L be more competitive with Core 2? When will it finally come out? How much will it cost? Actually, I can sort of guess on the last point that 4x4 will cost a lot more than a Core 2 Quad config as you will need a more expensive mobo, RAM, and two CPU packages.

    I *think* Anand plans to have an article delving into 4x4 and AMD's plans more in the future. Maybe he's still gathering data from AMD? (Sort of like squeezing water from a dry spongue at times, unfortunately....)
  • johnsonx - Thursday, November 2, 2006 - link


    more expensive....RAM

    I don't think you're right on that one; 4x4 CPU's will use the same RAM as AM2 CPU's do. The "more expensive RAM" requirement is only for Opterons, which of course use registered ECC memory. In fact, if your chosen mainboard has memory banks for both CPU's, then you could even save a little since 4 smaller DIMMs tends to cost a little less right now than 2 bigger DIMMs.
  • JarredWalton - Thursday, November 2, 2006 - link

    Except that like socket 940 vs. 939, I expect all 1207 boards to require registered DIMMs. I don't know of any dual socket board that doesn't.
  • Griswold - Thursday, November 2, 2006 - link

    The whole "catch" of 4x4 was that there are no ECC/Registered DIMMS required - at least that was the synopsis all the time. It should have very little to do with the socket itself, rather a matter of IMC, no?

  • Anand Lal Shimpi - Thursday, November 2, 2006 - link

    You're correct, 4x4 will use Socket-1207 CPUs but without Registered memory.

    Take care,
  • JarredWalton - Thursday, November 2, 2006 - link

    I stand corrected, though I have to say I'm still not at all interested in getting a dual socket motherboard. LOL I guess 1207 CPUs will have to support both registered and unbuffered DIMMs? I can't imagine AMD trying to get people to make sure they get the right type of CPU for the RAM they're using.

    Second thought: could they have mobos and CPUs that will support both registered and unbuffered DIMMs? I think they have the same keying, so it's possible, right?
  • smilingcrow - Thursday, November 2, 2006 - link

    Two dual-core 90nm 120W CPUs = No thank you.
    Two quad-core 65nm xW CPUs = interesting!
  • Jedi2155 - Thursday, November 2, 2006 - link

    I'm personally a extremely heavy multi-tasker and I can't wait for quad to a hit a more managable price range. At the moment, they're just beyond my reach for a CPU alone. Once it hits around 300-500 then I would definitely buy one, but these right now are still for the rich and video encoders.
  • AlabamaMan - Thursday, November 2, 2006 - link

    I am still amazed by the fact that a $300 E6600 consistantly beats the $700 FX62
  • Aikouka - Thursday, November 2, 2006 - link

    That fact, my friend, is why I'm purchasing an E6600 in this upcoming week :). Simply the best performance without overclocking for the buck.

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