PCIe x16 bifurcation to x4x4x4x4 then mixing Gen2 and Gen3 cards - will all be Gen2 speed?

Discussion in 'Processors and Motherboards' started by petreza, Nov 29, 2019.

  1. petreza

    petreza New Member

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    Does anyone know if the bifurcation specification requires that all the bifurcated channels must have independent timing? That is, if I bifurcate a x16 Gen 3.0 slot into x4x4x4x4 and then plug three Gen3 and one Gen2 cards, will all four cards operate at Gen2 speeds?

    Thanks!
     
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    Last edited: Nov 29, 2019
  2. petreza

    petreza New Member

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    asked Supermicro; they said they do not know - have never tested such a setup - but in general they think one card should NOT affect the speed of another even if they are plugged in the same slot (using bifurcation and passive slot splitters)
     
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  3. Kev

    Kev Active Member

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    Should not affect anything because the negotiation of the speed is done at the RC, root complex and each device is connected to a dedicated foot complex. This is purely from a system engineering point of view.
     
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  4. MiniKnight

    MiniKnight Well-Known Member

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    I'd think not, but this is one I'd like to hear what you find.
     
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    Tha_14 likes this.
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