XENON to have two PPC Cores?

Discussion in 'Console Technology' started by j^aws, Feb 7, 2005.

  1. Panajev2001a

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    Uhm...

    This new processor core seems to have VERY similar requirements/features to the cores used by the Xbox 2/Xenon's CPU: 2-way in-order cores with hardware Multi-threading (SMT), very high clock speed, etc...
     
  2. Pugger

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    This is a bit to technical for me Panajev2001a but could a modified G5 be described as "new" 64b PPC" ?
     
  3. Panajev2001a

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    Yes, but it would hardly come close to the frequency target they have barred major re-working of the chip which would present more troubles and more headaches than trying a more clean-sheet design (instead of taking the G5 and modifying it until it runs at those kinds of frequencies... yes, they could take the core... save some ALUs and stuff and redo everything else ;)).

    The G5 is a very wide and fairly complex beast and this is not what they looked for to be the basis for this new PowerPC core IMHO.
     
  4. one

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    A PPE in Cell, which is not derived from an older core, and a G5 (PowerPC 970) are only compatible by Power ISA + AltiVec.

    So, indeed, it matches well with what I guessed in the last year (here and here) about Sang Dhong, one of the core Cell architects, and his world-first 1GHz microprocessor :D

    http://www.isscc.org/isscc/2000/ap/ap/Ssn_5.html
    Though I don't think PPE in Cell and Xenon CPU core are the same thing because the former is pretty much unproven thing, is it in the leaked document that the Xenon CPU has in-order cores?
     
  5. one

    one Unruly Member
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    http://www.theinquirer.net/?article=20920

     
  6. archie4oz

    archie4oz ea_spouse is H4WT!
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    You mean PowerPC ISA.. :p
     
  7. one

    one Unruly Member
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    :) Anyway, "not derived from an older core" is a bit misleading, I should have written "not derived from an older core available on the market".

    So a "leaked info" at an Apple news site about a newly developed embedded Power processor (65nm PPC3xx) is apparently a fake or not related to Cell (and the Xenon CPU).
     
  8. Guden Oden

    Guden Oden Senior Member
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    It's more like well-HOPED, amongst the internet fanbois... ;) Dude, G5 is a HUGE chip. To hope for three of those, even modified ones, is completely unrealistic IMO. The G5 works in a very curious fashion with lots of oddball exceptions for how instructions may be issued together with what other instructions etc (read the Ars article on the subject), using THAT particular chip as a basis for an extremely cost-sensitive product like a console sounds really bad to me. Especially as MS voiced quite vocal dissatisfaction with the price of the original box in the past!
     
  9. DeanoC

    DeanoC Trust me, I'm a renderer person!
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    People who follow Beyond3D forums have known for some time the Xenon CPU isn't based on G5's....

    Do people listen to me, NO <grumble, grumble> :D
     
  10. pc999

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    We listen, in fact we would like to listen much more :wink: , to bad that it is impossible :( , anyway dont worry because we listen very,very,very carefull :D
     
  11. Entropy

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    Uhm, not to disagree with the general gist of your post, but the G5 isn't huge by any stretch. It's 60 mm2, and that's with 512kB cache. Three of those cores, and with 1 MB of shared cache, would come in at roughly 150 mm2 or so. This first Cell type processor that has been shown off is still 50% bigger.

    That said, it definitely seems a possibility that the xBox2 will use cores similar to the PE, in which case three of them is no problem in terms of die space, nor would that 3.5 GHz target be a problem even at modest power draw.
     
  12. Nite_Hawk

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    Not to pick nits, but the G5 on 90nm is a bit bigger (65.1mm2).

    Nite_Hawk
     
  13. Entropy

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    Not to pick nits?!? :D
    I don't know where you got that number (but it seems to have more significant digits than mine, although mine is from IBM). Still, the 970fx is not just core+cache, there is chip area devoted to driving pins and whatnot that wouldn't be triplicated, so my seat of the pants 150 mm2 is probably still in the ballpark. In fact, I wouldn't be surprised if they could squeeze it a little bit tighter still. So three cores of roughly 970 complexity would be a possibility in terms of chip size. In terms of power draw at 3.5 GHz however, forget it, even taking into account that the XBox2 diagram where from more lithographically optimistic days.

    Actually, given how tiny the PE is, Microsoft should be able to put more into the XBox2 CPU than just three of them + 1 MB of shared L2 cache. Particularly given Gates' comments about the power draw of the thing. But perhaps they opted to prioritize for manufacturability/cost.

    The XBox2 CPU is still a bit of a mystery, but three cores of PE type would seem to best fit the rumours floating about.
     
  14. Nite_Hawk

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    That was a very long reply to a very simple post. :D

    Btw, here's a link to where I got the size:

    http://www-03.ibm.com/technology/power/newsletter/august2004/files/powerpc_device_quick_look.pdf

    Nite_Hawk
     
  15. bbot

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    Maybe it's time to reconsider an old idea about xbox2. Maybe it will have three dual-core processors.
     
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