Memory bandwidth still critical.

Discussion in 'Mac Pro' started by hugodrax, Oct 20, 2007.

  1. hugodrax macrumors 6502a

    Joined:
    Jul 15, 2007
    #1
    Will the new chipsets increase the memory bandwidth? Right now the mac pro will do 21Gb/s but more cores will need more GB/s maybe 42Gb/s To really take advantage of large workloads you need more bandwidth to your memory once you increase the core counts. 21Gb/s is fine for 4 cores but at some point
    Intel will need to work on the memory side of the house.

    This is one of the things that made Crays so much powerful compared to PCs back then with measly memory bandwidth. I would laugh when people would say wow look my PII does 300mflops. And I would run the equivilant cray job on that PII and it would choke on the workload compared to the Cray EL.

    I would have to say just recently last 1 1/2 years have PC's finally caught up to the memory performance of the supers of the mid 1980s and 90s.

    ie: Mac Pro could do Cray C90 series workloads for example
     
  2. Eidorian macrumors Penryn

    Eidorian

    Joined:
    Mar 23, 2005
    Location:
    Indianapolis
    #2
    It'd be nice if you posted benchmarks.

    I'll have to dig up 1066 Vs. 1333 MHz for the quad.

    Current workstation = super computer? Really? :rolleyes:
     
  3. krunk macrumors regular

    Joined:
    Jan 29, 2004
    #3
    There are memory improvements with the next chipset, I'll leave it up to you to google the specifics.

    However, current and the next round of Xeon systems will still be bottlenecked by the FBDIMM memory, which is inherently more latent then other options. This is due to the serialization step that must be performed.

    FBDIMM's are a dying tech, I've spoken to apple engineers on this issue and they are aware of it...but of course, the ball is in intel's court.
     
  4. FF_productions macrumors 68030

    FF_productions

    Joined:
    Apr 16, 2005
    Location:
    Mt. Prospect, Illinois
    #4

    The price continues to drop!

    A week ago 4 gigs of ram cost 250 dollars, its now dropped to 235!

    http://eshop.macsales.com/item/Other World Computing/53FB2MPK04GB/

    2000th Post!
     
  5. krunk macrumors regular

    Joined:
    Jan 29, 2004
    #5
    This is true. I think the problems have less to do with price point and more to do with inherent bottlenecks in the design that cause them to underperform compared to straight registered DDR.
     
  6. MacsAttack macrumors 6502a

    Joined:
    Jul 2, 2006
    Location:
    Scotland
    #6
    NSS

    This news just in - Hard disk access speeds major bottleneck in modern computers! ;)
     
  7. thxdave macrumors member

    Joined:
    Aug 10, 2007
    Location:
    Florida
    #7
    I ordered a 2 gig chip for my MBP last night from OWC. I'm finally maxed out at 3 gigs total.
     
  8. hugodrax thread starter macrumors 6502a

    Joined:
    Jul 15, 2007
    #8

    8Gb of ram here :)
     
  9. thxdave macrumors member

    Joined:
    Aug 10, 2007
    Location:
    Florida
    #9
    I'd love to have more than 3 gigs in this MBP, but the 2.33's topped out at 3. When I buy my MP in few weeks (fingers crossed), we'll be talking about a bit more than 3 gigs. BTW, based on current speculation as to mobo/chipset, what memory chips will the next gen MP's use? Just wondering if I should start stocking up now or wait until I get the box.
     

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