How Many Cores in a Larrabee?

Initial estimates put Larrabee at somewhere in the 16 to 32-core range, we figured 32-cores would be a sweetspot (not in the least because Intel's charts and graphs showed diminishing returns over 32 cores) but 24-cores would be more likely for an initial product. Intel however shared some data that made us question all of that.

Remember the design experiment? Intel was able to fit a 10-core Larrabee into the space of a Core 2 Duo die. Given the specs of the Core 2 Duo Intel used (4MB L2 cache), it appears to be a 65nm Conroe/Merom based Core 2 Duo - with a 143 mm^2 die size.

At 143 mm^2, Intel could fit 10 Larrabee-like cores so let's double that. Now we're at 286mm^2 (still smaller than GT200 and about the size of AMD's RV770) and 20-cores. Double that once more and we've got 40-cores and have a 572mm^2 die, virtually the same size as NVIDIA's GT200 but on a 65nm process.

The move to 45nm could scale as well as 50%, but chances are we'll see something closer to 60 - 70% of the die size simply by moving to 45nm (which is the node that Larrabee will be built on). Our 40-core Larrabee is now at ~370mm^2 on 45nm. If Intel wanted to push for a NVIDIA-like die size we could easily see a 64-core Larrabee at launch for the high end, with 24 or 32-core versions aiming at the mainstream. Update: One thing we did not consider here is power limitations. So while Intel may be able to produce a 64-core Larrabee with a GT200-like die-size, such a chip may exceed physical power limitations. It's far more likely that we'll see something in the 16 - 32 core range at 45nm due to power constraints rather than die size constraints.

This is all purely speculation but it's a discussion that was worth having publicly.

Putting it all Together - Return of the Ring Bus Cache and Memory Hierarchy: Architected for Low Latency Operation
POST A COMMENT

101 Comments

View All Comments

  • del - Friday, August 15, 2008 - link

    Don't be a hater. :P Intel has got it goin' on right now. Believe in the POWAH of Larrabee... unless it proves to be a failure upon release.

    :)
    Reply
  • atlmann10 - Saturday, August 09, 2008 - link

    Think about this ok AMD originally was a private IBM cpu manufacturer. Then bought out and run as a side unit of INTEL, that was dropped after they were done with them. So in a way the were partners and I'm sure there was some friendliness. As it's always been said keep your friends close but your enemies closer. There have been some things especially in these past two years that struck me kind of odd. Such as AMD's graphics chips running fine on a x38/48 chipset and the physics collaboration things as well as a few other rumors. Then Nvidia starts spouting off about how they could kick INTELS A77 etc. Now AMD has a definite GPU coprocessor in ATI and they wanna break into the market of GPU's etc. They know that there will be graphics competition with Nvidia being there largest competitior because there dedicated to GPU's solely and have a reputation. However now AMD has some chips that compete straight on weakening Nvidia to a point. Then AMD is getting more and more out of there cpu's gpu's and chipsets so INTEl jumps in the CPU GPU market just like AMD. Either way it turns out more are going to go with INTEL cpu's and many other products where AMD is kind of a fringe player. Who would you rather compete against full on 2 major GPU manufacturers or attempt to kind of co-align yourself with there competetitor while the somewhat down. Then throw out a whole new way to do graphics that performs well Nvidia is already loosing market share. So more people try it and the same number of people go with ATI. That leaves a much lower market for Nvidia plus there paying back what some 200 million dollars in bad GPU's right now as well and a few other problems they been having. Now this is not anything I know but knowing INTEL loves to stick it to competitors when there weak think about it. Reply
  • benkantor - Wednesday, August 06, 2008 - link

    if you could fit 10 Larrabees on 143 mm^2, you could fit 40 Larrabees on 286 mm^2, not 20... :P Reply
  • MamiyaOtaru - Saturday, August 09, 2008 - link

    For the love of education. We've already been through this. See the end of page 6 through page 7 in the comments section.

    143mm^2 doesn't mean 143*143. It means 143 square millimeters. 286 square millimeters is twice as many, allowing twice as many cores.
    http://img379.imageshack.us/my.php?image=squaremmh...">http://img379.imageshack.us/my.php?image=squaremmh...

    The article is right and you are so very wrong.
    Reply
  • Barack Obama - Wednesday, August 06, 2008 - link

    Derek and Anand deliver again! Reply
  • KGR - Wednesday, August 06, 2008 - link

    I am not a profeesional about software and hardware that is why maybe this question can sound nonsense .
    If larrabee will have a software renderer and programmed by C++ is it possible that it is not depended on windows? I mean if it doesnt need direct X can we run the games on Linux also??
    Reply
  • npoe1 - Tuesday, August 05, 2008 - link

    I enjoyed reading this so much. I think that this kind of articles is what Anandtech needs; I usually go to Arstechnica to read things like this one.

    Again, thanks!
    Reply
  • TrEmEnDo - Tuesday, August 05, 2008 - link

    I am definitely impressed with this new development and I expect that this technology will be disruptive down the road, however I feel that somehow they are about to commit another of their megalomaniac mistakes.
    Has anyone stopped for a sec and look where all gaming industry is heading into? Are PCs the future gaming platform? Maybe I am missing something but aren't the big guys already struggling to retain a 'decent' percentage of the multibillion gaming pie (PC gaming alliance anyone...)? I believe that whether us, tech enthusiast, hardcore pc gamers like it or not, it is the console arena where the big guns are going to be playing in a few years from now.
    Guys, we are seeing this happening everyday, we see tittles appearing and disappearing everyday b/c companies don't want to commit the resources to develop games for more than one or two platforms (normally doing a sloppy work BTW). Now that the grandpas of graphic hardware had manage to get DX/D3D derived engines into the last gen consoles (xenos, RSX) and a terribly inertial and rigid developer community avoids and whines about how difficult is to program for the few hardware 'jewels' that we have already in our hands (Cell/RV770/G200) do you think anyone except Intel is in the mood for yet another graphics industry spin?

    I have no doubt that this new development will have its own niche application or someone will definitely find something appropriate for it, but to say that Larrabee CAN do graphics and to say larrabee will kick ass so bad that in 3 years from now we all will be gaming from a Larrabee containing computer are two very different things.
    Congrats to Intel as the fathers of the creature, and congrats to us to see the tech world moving on....but just don't think this will change the world as we know it.
    Reply
  • hooflung - Tuesday, August 05, 2008 - link

    They are doing something very AMD like and taking it a step further and tossing in a few Power ideals in. I just wonder what the power profile will look like and who will partner up with Intel for it.

    I am sure they will have 4+ of these cores built into integrated chip sets for OEMs and laptops to really boost those areas. And people who buy laptops will see that they can get a desktop with 'bigger larrabee' and play their games faster than their budget/laptop computer.

    So it does make sense. However, it is an empire made on a lot of ifs. It will be fun to watch. Thanks anandtech for the informative article.
    Reply
  • christophergorge - Tuesday, August 05, 2008 - link

    is it just me or does it look like another transmeta crusoe in the making? Reply

Log in

Don't have an account? Sign up now