AnandTech reader Grant Vezina pointed out in the comments to my last post that Intel properly documents almost all Ivy Bridge die sizes in the mechanical specifications pages of its Ivy Bridge datasheets. That's what I get for feeling accomplished after taking apart the Zenbook Prime and measuring its Core i7-3517U. Only the 4C/GT2, 2C/GT2 and 2C/GT1 dimensions are documented while the 4C/GT1 configuration is Vezina's own calculation based on available data. 

Ivy Bridge Die Comparison
CPU CPU Cores L3 Cache GPU Config Dimensions Die Area
Ivy Bridge HE-4 4 8MB GT2 8.141 x 19.361 mm 159.8mm2
Ivy Bridge HM-4 4 6MB GT1 7.656 x 17.349 mm 132.8mm2
Ivy Bridge H-2 2 4MB GT2 8.141 x 14.505 mm 118.1mm2
Ivy Bridge M-2 2 3MB GT1 7.656 x 12.223 mm 93.6mm2

There are a few items of interest here. The GT1 configs appear to be narrower than the GT2 counterparts, otherwise these chips just differ in terms of die length. Haswell will likely continue the trend. 

Why did Intel stop at 16 EUs for the GT2 in Ivy Bridge? Cost is an obvious concern (Intel likes making tons of money) but at some point you need to scale up memory bandwidth to make use of additional compute horsepower. Haswell will address this issue while it scales up to 40 EUs. Intel could have implemented eDRAM with Ivy Bridge, however only one customer was really asking for it and wasn't interested in paying a significant premium for it. Why pay now when Haswell will deliver it less than a year later?

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  • mavere - Thursday, May 31, 2012 - link

    Too bad Intel and Apple couldn't work out a deal on a beefier Ivy Bridge; it would have a been a pretty good setup.

    Apple would foot the bill on volume production because they sell so much of one SKU, while other companies would be able to use the chips on some high end units.
    Reply
  • JMS3072 - Thursday, May 31, 2012 - link

    "however only one customer was really asking for it and wasn't interested in paying a significant premium for it."

    What's your source for that?
    Reply
  • CeriseCogburn - Friday, June 01, 2012 - link

    APPL standard operating prodecure Reply
  • iwod - Thursday, May 31, 2012 - link

    The most interesting fact is that they actually produce the die for each specification. And that is something new to me because we always thought GT 1/2 were only disabled die.

    That would also means Intel has mastered another technique of yield and flexibility in its Fab.
    Reply
  • CeriseCogburn - Friday, June 01, 2012 - link

    So scowling "harvested" while blabbering binning and defective parts just won't do ?
    :-)
    I thank my lucky stars.
    Reply
  • fic2 - Friday, June 01, 2012 - link

    I think that Grant's supposition on this was that there was a large enough die size difference between GT 1/2 that it made sense to Intel to have different die for each. They can probably get several more GT 1s per wafer than GT 2s. Also, since GT 1s are much smaller the number of defective chips/wafer is probably smaller.

    Using http://mrhackerott.org/semiconductor-informatics/i...
    and using 300mm wafer and default parameters since I don't know anything about wafer layout it looks like Intel can produce up to ~1400 more die per wafer for the M-2 GT1 than the H2 GT2. So, definitely worth it. Even at 75% yield that is over 1,000 die they can sell and probably $1-200,000 extra $$$.
    Reply
  • CeriseCogburn - Saturday, June 02, 2012 - link

    Wait, I thought it was all about not wasting precious resources, and bringing computers to the people of the world ?!!
    If Intel can share this gift with 1,000 more people of the world, it would be selfish and evil if they did not.
    Reply
  • madooo12 - Saturday, June 02, 2012 - link

    Intel is selfish and greedy, they won't share it for free you know Reply
  • seapeople - Sunday, June 03, 2012 - link

    I think it would be better if Intel was taken over the by the government and forced to sell their CPUs to the world at just a hair above manufacturing cost. Then all their employees should share equally in the profits and receive free health care.

    That would be much less selfish and greedy.
    Reply
  • CeriseCogburn - Monday, June 04, 2012 - link

    Better than getting a super gimped 25 different ways 5 year old brand new core hacked harvested mhz AMD core, isn't it madooo12 ?

    Think of the bazillion wafers amd wastes as they constantly rebrand and gimp their completely harvested cpu line up.
    No wonder they can't make dime one.

    Maybe amd should rename itself to "Wasted Wafers !"
    Reply

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