PCI-Express question

Hey all just need to know something here...

Let's say there's a motherboard with PCI express 2(x16) capable slots and an older one with PCI express 1(x16) slots. Using the NVIDIA GTX 470 as an example, will it perform 100% the same on both motherboards with the same hardware? Does it lose any features or performance if it's in a pci express 1(x16) slot(the card is PCI express 2 capable, but as far as i know not dependant)?

Thanks a lot!

Tom :D
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  1. Best answer
    PCI Express x16 2.0 can handle more bandwidth from the GPU than a regular PCI Express x16.

    You wont lose any features.

    even though the gtx 470 doesnt need full PCI Express x16 2.0 bandwidth, there will still be slight performance gains over the regular x16 slot.

    The performance gain would be around 5% at the max.
  2. Ah I see, so the GTX 470 is too powerful for the 1.0/1.1 slot and needs a 2.x slot to use 100% of it's power? Also I heard 2.x slots can send more power to the GPU(150W?) and 1.x only 95W is this true? Was thinking of getting a GTX 460 instead which only uses 160W max as opposed to the 215W 470 - will this work @ 100% speed?

    & thanks for your prompt knowledge
  3. Best answer selected by Koozwad.
  4. i have not heard about the wattage cap on PCIE slots. Regardless if a GPU supports PCIE 2.x and you put it in a PCIE x16 *(Gen1)* slot, you will lose "optimization" i guess you could call it.

    if you had identical GPU's just say two Nvidia 9600gt cards and one was x16 and one was x16 2.0 the one with the PCIE 2.0 would perform slightly better just because of optimization. It would not perform better because of bandwidth limitations or power limitations.

    here is a quote from another forum that i dug up from toms hardware"

    "Picture driving a Prius on an 8 lane highway with a 200mph speed limit and no other traffic. Now increase the speed limit to 400mph. That's about how useful PCIe 2.0 is to any 8800 class GPU (or any modern day GPU for that matter).

    Oh and in case you were wondering, PCIe 2.0 is fully backwards compatible with PCIe 1.X."


    its an older post but it gets the point across. The slots are backwards compatible. but imho it depends on your budget as to which is the better investment because you would be losing less performance with the GTX 460 over the 470 but the loss difference would be minimal. the GTX 460,465,and 470 are all about the same in the price to performance aspect. don't get a gtx 480 unless you have nothing else to spend your money on.

    i wouldn't base a purchase on a GPU over the x16 vs x2.0 slot. but that's just me

    hope this helps.
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