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    PCI-E Scaling? Confused.

    Discussion in 'e-GPU (External Graphics) Discussion' started by Agent CoolBlue, Dec 25, 2012.

  1. Agent CoolBlue

    Agent CoolBlue Notebook Deity NBR Reviewer

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    Hey all,

    I am trying to read up on PCI-E Scaling and am seeing PCI-E 1.0 @ 4x,8x,16x, PCI-E 2.0 @ 4x,8x,16x, and so forth.What type of connection will my 2560P and PE4L 2.1b represent. PCI-E 2x @ x? I Just wondering which one my connection would be. What determines the "X"? I know the 2560P expresscard slot will be PCI-E 2.0 but not sure what determines the X.

    Also, does the percentage next to the scaling results, I.E. 88%, represent the performance relative to a full PCI-E 3.0 solution. In this case, 88% would be a 22% loss of performance?

    Thanks!
     
    Agent CoolBlue, Dec 25, 2012
    #1
  2. sgogeta4

    sgogeta4 Notebook Nobel Laureate

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    PE4L 2.1b supports PCIe 2.0 x1 and your expresscard is limited to PCIe 2.0 x1 anyways. PCIe 2.0 has double the bandwidth of PCIe (1.0), hence PCIe 2.0 1x = PCIe 1.0 2x. According to the scaling post:

    Compared to x16 2.0 we can summarize that there is 50% performance loss at x1 1.0 and 20% performance loss at x2 1.0 link speeds. Or x2 1.0 is 60% faster than x1 1.0.
     
    sgogeta4, Dec 26, 2012
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  3. tondy

    tondy Newbie

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    the x4 - x16 is number of PCI lanes available for data.
    PE4L can do 1x (1 lane) at PCI spec 2.0 = 5Gb of bandwidth total
    vs. 16x @ 2.0 = 16 x 5Gb = 80Gb total bandwidth available = 16x more than 1x (or 1x = 1/16th of 16x link)
     
    tondy, Jan 1, 2013
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