CPU of Mac Pro Early 2009...

Discussion in 'Mac Pro' started by risingforce, Jun 9, 2009.

  1. risingforce macrumors newbie

    Joined:
    May 15, 2009
    #1
    Hello. I have a 2.66GHz mac pro 4core Nehalem. Looking at the website I think the intel processor Mac Pro to fit the early 2009 include the W3500 series. Is it true?

    Is that if I'm correct, I do not understand why Apple has not mounted the X5000 series with QPI for 6.4GT/sec, instead of 4.8GT/sec of the W3500.

    Greetings
     
  2. Umbongo macrumors 601

    Umbongo

    Joined:
    Sep 14, 2006
    Location:
    England
    #2
    Because they would cost Apple $675 more. I doubt many users are constrained by the lower bandwidth either.
     
  3. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #3
    W3520 to be exact. :p

    Not all of the parts in a series have the max bandwidth (6.4GT/s), as per Intel's design. Though technically possible, it's also a waste of money to use any of the 55xx parts in a Single Processor board, as Umbongo indicated. ;)

    Check here, for more details. Gainestown is the 55xx parts (Octo's), and the W35xx parts (Quads) are the Bloomfield (UP Server section).
     
  4. risingforce thread starter macrumors newbie

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    May 15, 2009
    #4
    Then, the difference in bandwidth is not as important? Is that correct? That is, that the overall performance is not affected by the lower bandwidth?

    But if Intel i7 has a bandwidth greater than the Xeon .. Where is the advantage of incorporating Xeon Nehalem instead i7?

    Greetings
     
  5. SydneyDev macrumors 6502

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    Sep 15, 2008
    #5
    I'm not sure but would it need 1333 ram for 6.4GT mode? The Mac Pro only has 1066 ram so maybe it doesn't matter.
     
  6. Umbongo macrumors 601

    Umbongo

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    Location:
    England
    #6
    Nope. The 8 core 2.66Ghz and 2.93GHz Mac Pros have QPI set at 6.4GT.
     
  7. eelpout macrumors regular

    eelpout

    Joined:
    Oct 30, 2007
    Location:
    Silicon Valley
    #7
    Though Apple seems to charge as much as if the W55xx part was being used. ;)

    Does anyone know if the single quad Nehalem Mac CPU can be replaced with something faster (when prices come down)?
     
  8. risingforce thread starter macrumors newbie

    Joined:
    May 15, 2009
    #8
    In theory if you can replace the processor because the socket is the same, but would have to remove the heatsink, clean the thermal paste, put the new processor, apply thermal paste and mount the heatsink.

    So yes, goodbye to the warranty.

    For if the 8 cores with a mounted a CPU's QPI to 6.4GT, I do not understand what the hell I have the 4 core :(

    Returning to my earlier question, where is the advantage of riding Xeon CPU's instead of the i7? Because if it is true what I read online, the i7 perform better than Xeon Nehalem :( I come from the PC world and I have spent the money on the Mac Pro thinking that this money was well spent a machine more powerful than a PC but if anyone now that the Xeon nehalem yield less than i7 because I took a disgust.
     
  9. Umbongo macrumors 601

    Umbongo

    Joined:
    Sep 14, 2006
    Location:
    England
    #9
    Apple chose the Xeons because they support ECC memory. The i7 processors do not. The Xeons and the i7 perform the same at the same clock speeds. The advantage of the i7 platform is that on many boards you can overclock the processors, set supported memory speeds to something other than 1066MHz and change the QPI to the speed you want. You might be able to do this on non-Apple Xeons too, I haven't checked.

    I really wouldn't get bothered by the QPI speed, I doubt it will be a severe bottleneck for you.
     
  10. SydneyDev macrumors 6502

    Joined:
    Sep 15, 2008
    #10
    Server parts are not always faster than desktop, sometimes they are just more reliable. Servers have to run 24/7 and not break.
     
  11. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #11
    Keep in mind, that the stock default values, the memory can't exceed the QPI bus. So when the spec is for a lower QPI, you'll notice it uses slower memory. 800 or 1066 rather than 1333MHz DDR3. ;) That bandwidth may hit the limit, provided you're using the system with all PCIe slots running simultaneously (not just filled), and the memory banging away at full throttle in tripple channel mode. Not much software is capable though.
    It doesn't have to use 1333. Slower memory can be used, but assuming your software and usage take advantage of everything it's capable of, you'd be throttled a little, due to the lower clock. Again software/usage come into play.
    You can put a Dual Processor Xeon in it, as the CPU can shut off the second QPI channel. Not worth anything though, unless the highest clocked 55xx exceeds the highest clock of the W35xx parts. Beyond that, who knows, as the chipset will have to support whatever you stick in, or it's a wasted effort. :eek: ;)
    In this case, the Core i7 (high performance desktop) is identical to the W35xx parts, save the ECC functionality.

    I'd expect this adage to hold true however, on the Core i5 parts (mainstream desktop) that haven't yet been released.
     

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