PCI-E 2.0 vs PCI-E Gen2

Hi all!

I'm trouble finding information explaining what it is and what it can do for me and also what's the diference between

"PCI-E 2.0" and "PCI-E Gen2"

because I'm looking to SLI a 'MSI N580GTX Lightning Xtreme Edition' card and since I have a 'MSI 990FXA-GD65' mainboard which on the specs says:

PCI-Ex16 2
PCI-E Gen Gen2 (1x16, 1x8)

I'm concerned that if I SLI the cards will run at 8x and not 16x.

Could you help understand it ?
12 answers Last reply
More about gen2
  1. Hmm.I had the 890FXA-GD65 and it could do x16/x16.They are practically the same board except for SLI support and voltage changes for the CPU but I don't see why the 990FXA can't do x16/x16.It might be SLI related but i'm not sure.

    Either way you won't be able to notice a difference between x8 and x16.The performance loss is only around 10%.
  2. Do you know the difference between FXA and FX versions?
  3. PCI Express Gen2 refers to the second generation of the PCI Express standards ( PCIE 2.0) so PCI Express 2.0 is the same the PCI Express Gen2
    MSI refers to that both PCI Express slots are Gen2 X16 but when a second GPU is populated one of the PCI Express slots will be routed as x8.

    you won't notice any difference between X16-X16 versus X8-X8 and read this
  4. whatever, the 8800 ultra, GTX 580 use the same PCIE 2.0 standards...
    and benchmarks indicates that there's a slight difference in performance isn't noticeable unless you run a 3D Mark or something like that .. you get more bunch of numbers...
  5. dirtyferret said:
    those tests use the nvidia 8800 ultra as a top end card, the nvidia GTX580 is slightly more powerful then that....

    watch this video about SLi/CF FAQ and scroll to 3:45 to 4.12 and you'll find the answer....
  6. Just for future reference the GTX580 is a much more powerful card than the 8800 Ultra.Which means that it has a lot more bandwidth.Technically it would be more hampered by the x8 slot than a 8800 Ultra but still the difference of a x16 and x8 slow is very minimal.

  7. Guys, first of all thanks for your enthusiastic input!

    I believe this video:


    ... is somewhat self explanatory but what do you think ?

  8. dirtyferret said:
    it answers nothing but a product plug (or those stupid enough enough to believe product plugs)

    Tom's did a review with GTX480 in x8 SLI (you can go search for that) and found a slight drop in gaming when compared to the GTX480 in x2 16 SLI

    with the GTX580 having more power then the GTX480, one (with intelligence) would expect a small drop in performance also. it's not a significant drop but it is there.


    i'm just laughing out loud, did you read my post above ? i said " there's a slight difference that isn't noticeable is 3% being noticeable ? you won't notice it while gaming you'll notice it if you run a benchmark program
  9. dirtyferret said:
    it's a minor issue, in real life you wont notice the difference between your configuration and one that runs 2x16 in SLI/CF.

    so, you did just answer yourself....
  10. @ purple stank, look at the video OP posted and you'll find the answer about the GTX 580 full bandwidth...
    @ OP, now you already know the difference, there's no difference and if there is it's just logical :D
  11. So it seems! :)

    Thanks again for all your input! :)
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