G70, G71, R520, R580 die size discrepancy

Discussion in 'Architecture and Products' started by atomt, Mar 6, 2006.

  1. atomt

    Newcomer

    Joined:
    Nov 1, 2004
    Messages:
    61
    Likes Received:
    4
    Beyond3D list the folowing as dimensions (from reviews )
    G70 - 334mm^2
    R520 - 288mm^2
    R580 - 352mm^R2
    V530 - 156mm^2

    Techreport
    http://techreport.com/reviews/2006q1/radeon-x1900/index.x?pg=1
    G70 - 333mm^2
    R520 - 263mm^2
    R580 - 315mm^2
    RV530 - 132mm^2

    Nvidia Slides
    http://www.nvnews.net/vbulletin/showthread.php?t=65835
    G71 -196mm^2
    G73 - 125mm^2
    R580 - 352mm^2
    RV530 - 149mm^2

    I estimated the G71 die size to be ~ 250mm^2. I ASSUMED that the heatsink
    mounting holes are the same for 7900GT and 7800GT boards. I measured the die dimension and scale it using a G70/334mm^2 as a reference.

    From this pictures, where what appears to be a G73 on a 7900GT board,
    I estimate the G73 to be ~ 150mm^2. As a reference , Samsung GDDR3
    FBGA package is 154mm^2 (from Samsung specs)
    http://www.nvnews.net/vbulletin/showthread.php?t=65257

    Beyond3D measurements for Nvidia die size is same as Techreport. Techreport estimates
    for ATI die sizes are smaller than Beyond3D.

    A ruler is not accurate but 25% difference?

    Nvidia and ATI count transistors differently but it appears that Beyond3D, TechReport
    and Nvidia use different rulers as well. Samsung ruler is different from Nvidia as well.

    90nm transistor area is 67% that of 110nm. In a shrink, due to ML and routing limitation,
    the shrink is < ideal. Even assuming an ideal 67% shrink, G71 die size = 0.67 x 334mm^2
    = 224mm^2. Is Nvidia that much better at fitting 300M transitors into 196mm^2 while ATI
    needs 288mm^2 for R520 321M?
     
  2. Arun

    Arun Unknown.
    Moderator Legend Veteran

    Joined:
    Aug 28, 2002
    Messages:
    5,023
    Likes Received:
    299
    Location:
    UK
    Obviously, the middle figures are fucked. Sounds like a 1mm error on both dimesions to me, or being lazy and linearly scaling based on NVIDIA's density...

    I'd beware personally - you don't know if it's the same revision etc.

    At hinted towards in the other G71 thread, G71's transistor count is below that of G70. NVIDIA's transistor density IS higher, though.


    Uttar
     
  3. Sunrise

    Regular

    Joined:
    Aug 18, 2002
    Messages:
    306
    Likes Received:
    21
    I just looked at this myself and i came to the following conclusion:

    It looks like NV compares physical die size of R580 with their die size for G71 from the data sheets (before the die is cut from the wafer) which is as wrong as it gets when trying to compare both cores.

    You should ignore that altogether, as this is quite missleading.

    Let´s wait for Dave´s or Degustator´s measurements of an actual G71 core, for further judgements.
     
    #3 Sunrise, Mar 6, 2006
    Last edited by a moderator: Mar 6, 2006
  4. atomt

    Newcomer

    Joined:
    Nov 1, 2004
    Messages:
    61
    Likes Received:
    4
    That picture ain't a G71, so unless Nvidia have a 160mmm^2 chip. The PCI-E signals are not even connected to the package.

    G71 transistor count need to be 10% less than a G71 to shrink from G70 334mm^2 to
    196mm^2 assuming an ideal 67% shrink. So G70 have 10% useless transistors?
     
  5. Arun

    Arun Unknown.
    Moderator Legend Veteran

    Joined:
    Aug 28, 2002
    Messages:
    5,023
    Likes Received:
    299
    Location:
    UK
    I suspect a NV43 (6600GT) chip, personally:
    http://www.beyond3d.com/misc/chipcomp/?view=chipdetails&id=71

    Not sure, but if you look at past generations, it doesn't feel impossible (although G70 wasn't really a "next generation" chip.)

    Uttar
     
  6. atomt

    Newcomer

    Joined:
    Nov 1, 2004
    Messages:
    61
    Likes Received:
    4
    The chipcaps location is different. The package is identical down to all chip caps
    position to G73 pictures in vr-zone and others. The funny thing is that the card
    have 8 Samsung 32-bit GDDR3, so 256-bit memory interface. On top of that,
    the PCI-E signals are not even connected. Note the 2 rows of unused solder pads all around the chip package. Dailytech have since removed the card picture but this site have
    the original dailytech pics. Since that chip is smaller than 196mm^2, so it ain't
    a G71, what is that? A G73 with 128-bit memory interface on a 7900GT board?
    The package pins out are different.

    http://publish.it168.com/2006/0221/20060221256501.shtml
     
  7. atomt

    Newcomer

    Joined:
    Nov 1, 2004
    Messages:
    61
    Likes Received:
    4
    Die saw street

    Die saw street is 80um for 90nm low-k. So not significant.

    We just have to wait until some get hold of a board and use the "correct" ruler.
     
  8. atomt

    Newcomer

    Joined:
    Nov 1, 2004
    Messages:
    61
    Likes Received:
    4
    TechReport ATI die sizes are dffferent from Nvidia and Beyond3D but their
    Nvidia chips measurements are close to Beyond3D. TechReport have 2 rulers,
    one for ATI and one for Nvidia? ATI R580 does look pretty big. I am inclined to
    trust Beyond3D since Dave measure the die size for almost every card. Other
    sites don't do it consistently. Most of the time, no die measurements.
     
  9. rwolf

    rwolf Rock Star
    Regular

    Joined:
    Oct 25, 2002
    Messages:
    967
    Likes Received:
    51
    Location:
    Canada
    Don't forget that ATI chips have built in support for GDDR4 and virtual card memory. This takes a fair number of transistors.
     
  10. Sunrise

    Regular

    Joined:
    Aug 18, 2002
    Messages:
    306
    Likes Received:
    21
    Certainly not that significant, but there´s still a disparity between those sizes, then.
     
    #10 Sunrise, Mar 6, 2006
    Last edited by a moderator: Mar 6, 2006
  11. Sunrise

    Regular

    Joined:
    Aug 18, 2002
    Messages:
    306
    Likes Received:
    21
    Well, that would be a direct question to Dave. I´m also inclined to believe his 3D tables, but something doesn´t make sense here.

    Dave, if you are out there, can you please confirm that you did those measurements yourself? Not just on R580, but also on G70? I´ve just accidentally stumbled over the die sizes of G70 and R580 respectively, and while G70 looks to be quite big, you have it listed smaller than R580. Is that actually the case ?
     
    #11 Sunrise, Mar 6, 2006
    Last edited by a moderator: Mar 6, 2006
  12. Xmas

    Xmas Porous
    Veteran Subscriber

    Joined:
    Feb 6, 2002
    Messages:
    3,298
    Likes Received:
    137
    Location:
    On the path to wisdom
    It seems to me the B3D figures for R520 and R580 are off. R580 should be smaller than G70.

    I've always thought G70 was much too big in relation to NV40 (which wasn't exactly economic regarding transistors either) and had expected around 250-260 million transistors for a 6 quad part before its launch. I guess after good initial results from G70, they thought the transition to 90nm along with a little "cleanup effort" could keep them competitive while shifting all resources to future projects.


    Less than 0.5%.
     
    #12 Xmas, Mar 6, 2006
    Last edited by a moderator: Mar 6, 2006
  13. Sunrise

    Regular

    Joined:
    Aug 18, 2002
    Messages:
    306
    Likes Received:
    21
    Yeah, pretty insignificant, actually. Should´ve worded that differently. ;)

    It´s funny though, that no one even questioned those die size measurements until now.
     
  14. silent_guy

    Veteran Subscriber

    Joined:
    Mar 7, 2006
    Messages:
    3,754
    Likes Received:
    1,379
    <Pendantic mode on>
    Hmmm. It's a bit more than 1% actually. Assume a scribe of 80um (aggregate, both sides) for 200m2, then you get:

    (sqrt(200mm2)+0.08m)^2 - 200 = 2.3/200 = 1.15%

    But are you sure it's 80um for both sides and not 160um? That would increase the difference to 4.5 mm2.
    <Pedantic mode off>
     
  15. atomt

    Newcomer

    Joined:
    Nov 1, 2004
    Messages:
    61
    Likes Received:
    4
    Saw street/Dicing blade

    The saw street is 80um. The cut (kerf width) is always slightly wider than the blade used.
    I can't remember the exact percentage achievable since it have been a long time since I worked in dicing but it should be ~ 50%. Assuming a 20um (0.8mil) thickness blade is used, the kerf width is 30um leaving 25um each on both sides.

    http://www.flipchip.com/services/die_level/dicing/

    Bottom line is that it is still insignficant compared to the discrepancy in die sizes.
     
    Jawed likes this.
  16. Razor1

    Veteran

    Joined:
    Jul 24, 2004
    Messages:
    4,232
    Likes Received:
    749
    Location:
    NY, NY
    Was the original die size of the g70 a bit bigger then expected?
     
  17. atomt

    Newcomer

    Joined:
    Nov 1, 2004
    Messages:
    61
    Likes Received:
    4
    Assuming B3D measurements of G70 is correct (334mm^2), and Nvidia R580 slide of R580 being 352mm^2 is the same as B3D measurements, the G71 die size claimed by Nvidia slides seem too small (it appears like either 186mm^2 or 196mm^2 in the slide)

    I measured the G71 die size in the picture. Since there is no scale, I used the heatsink mounting holes as a reference and compare that with a G70. I approximated the G71 die size to ~ 250mm^2.

    The 2 question I have is :

    1. A shrink of 334mm^2 to 196mm^2 is a 58% shrink. A 90nm transistor is 67% the area of 110nm transistor. Shrink efficiency is often lower because the analog/buffer circuits do not shrink as much due to need to maintain drive currents
    (interface to PCI-E/GDDR3, DVI, RamDACs)

    2. That would make G71, almost 1/2 the size of R580. Is it possible that G71 architecture so much more efficient or R5xx is ATI's GeForce FX?
     
  18. Jawed

    Legend

    Joined:
    Oct 2, 2004
    Messages:
    10,873
    Likes Received:
    767
    Location:
    London
    I was under the impression that TSMC's 110nm is a half-node, meaning that some features are shrunk, but others are not.

    If that's so, then it means that 110nm produces a larger die than would be expected.

    It would also mean that %age scalings from 130nm to 110nm and from 110nm to 90nm are invalid. Let alone the reasons given earlier for the way that different kinds of features (e.g. RAM) scale differently with varying processes.

    So, all in all, it seems like a fools-errand to evaluate die size at 90nm based on 110nm.

    Jawed
     
  19. trinibwoy

    trinibwoy Meh
    Legend

    Joined:
    Mar 17, 2004
    Messages:
    10,430
    Likes Received:
    433
    Location:
    New York
    Even so, based on what you've pointed out, it makes the < 200mm^2 claim for G71 even more ridiculous.
     
  20. fbomber

    Newcomer

    Joined:
    Jun 9, 2004
    Messages:
    156
    Likes Received:
    17
    Maybe the chip is less complex, transistor count wise (less rops, pipes, or whatever), than the g70, but ends faster because of the clock speed. The real monster would be the 2 chip version.
    This would explain some important developer hinting about a 2 chip reference card from a major IHV.
     
Loading...

Share This Page

  • About Us

    Beyond3D has been around for over a decade and prides itself on being the best place on the web for in-depth, technically-driven discussion and analysis of 3D graphics hardware. If you love pixels and transistors, you've come to the right place!

    Beyond3D is proudly published by GPU Tools Ltd.
Loading...