Macpro3,1. The last FSB of its kind. FSB vs QPI, major difference?

Discussion in 'Mac Pro' started by Korican100, Jul 29, 2013.

  1. Korican100 macrumors 6502a

    Korican100

    Joined:
    Oct 9, 2012
    #1
    So I have a Macpro3,1, decked out nicely. But I always feel behind because of FSB.

    Can someone tell me how MUCH slower I am with a FSB over QPI?
    Are there any pros if any using FSB. Any drawbacks of QPI?

    What are the major speed difference in QPI? And in what practical applications would I see these speed increases using QPI over FSB?
     
  2. mif macrumors regular

    Joined:
    Feb 16, 2010
    Location:
    home
    #2
    Memory intensive applications like Nehalem, i think.
     
  3. pastrychef macrumors 601

    pastrychef

    Joined:
    Sep 15, 2006
    Location:
    New York City, NY
    #3
    I think Wikipedia explains what QPI is better than I ever could.

    Here, you can see how different bus speeds can affect graphics cards. That's not the only thing that bus speeds affect, but it is the best example that I could think of off the top of my head.
     
  4. Korican100 thread starter macrumors 6502a

    Korican100

    Joined:
    Oct 9, 2012
    #4
    wow thanks for that barefeets link. I have the GTX680 in my macpro3,1. It says I would get double the performance out of it if I had a 5,1!

    Jeeze louise!

    FCPX feels fast on my machine, so I can only imagine how it would feel on 5,1!
     
  5. pastrychef macrumors 601

    pastrychef

    Joined:
    Sep 15, 2006
    Location:
    New York City, NY
    #5
    I started to realize that bus speed was becoming an issue when I switched out my GTX 285 for a GTX 670. That was when I got a 5,1 to replace my 3,1 and got a GTX 680. Everything has felt a bit snappier. But it could well be a placebo effect...
     
  6. Korican100 thread starter macrumors 6502a

    Korican100

    Joined:
    Oct 9, 2012
    #6
    so its not a "very noticeable" speed increase?
     
  7. pastrychef, Jul 29, 2013
    Last edited: Jul 29, 2013

    pastrychef macrumors 601

    pastrychef

    Joined:
    Sep 15, 2006
    Location:
    New York City, NY
    #7
    I think I notice it, but, again, it could just be my imagination because I don't have any hard numbers to show.
     
  8. MacVidCards Suspended

    Joined:
    Nov 17, 2008
    Location:
    Hollywood, CA
    #8
    Note that BMD doesn't encourage Resolve to be used on 3,1 for this very reason. They even have a "If you must use a 3,1, we have these lowered settings for it" handicap to get useable frame rates while working.

    I still love my 3,1 but it is the "bottleneck" in the machine.
     
  9. BJonson macrumors 6502a

    BJonson

    Joined:
    Aug 26, 2010
    #9
    I just went from a 3,1 to a 5,1 and immediately felt the difference.
     

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