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Expected Performance of PCI-e 2.1 and 3.0 Cards in a PCI-e 1.1 slot?

As the title describes.... I'd like to know if I could throw a card like a HD 6850/6870/7850 or GTX 650 Ti/660/660 Ti in my mobo and get good performance.

It would go in a Dell Precision 490 Workstation that has (2x) Xeon 5355 Quad Core CPUs (8 Cores) running at 2.66ghz, 1333 FSB, and each having 8mb of shared cache, 16Gbs of RAM, 2 SSDs and a Velociraptor for storage. This PC is mainly for editing HD Video, but I'd also like to play a few games as well.

Thanks for your patronage!
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  1. Best answer
    I have nearly exactly that machine, a Dell Precision 490, but with 3.0 Ghz processors instead of the 2.66. It isn't a stellar performer in CPU limited games like Starcraft 2. But in shooters, it is absolutely fine.

    So to answer your question, the HD 7000 series are reputed to NOT work at all on PCI-E 1.1 and earlier, due to power routing strictly adhering to the PCI-E 3.0 standard. The Nvidia's (PCI-E 3.0) don't have that issue, so if you were to add a current generation video card into the Dell, I would recommend a GTX600 series card.

    Other than that, bandwidth of the PCI-E bus is sufficiently high even at the PCI-E 1.0 standard for a card in the league of GTX 660Ti. You shouldn't notice much, if any performance degradation. I do remember from memory that the Dell Precision 490 has only 1 PCI-E power cable, so the GTX660 series is about as powerful as you can toss in there, in the stock configuration.

    In case you were curious, here are some results (BF3, extreme resolution, frame rates of cards of the current generation as a function of PCI-E lane reduction) from the excellent review site TechPowerUp:



    Taken from the full review:

    http://www.techpowerup.com/reviews/Intel/Ivy_Bridge_PCI-Express_Scaling/6.html

    I must caution you, that the way the test is conducted, the HD 7970 card is ran on a PCI-E 3.0 compatible board (same as the GTX 680), but the board itself has a BIOS option that allows you to toggle the signalling config of the PCI-E slot. I quote:

    "This review is made possible thanks to an awesome BIOS option given to us by ASUS ROG Maximus V Gene motherboard, which allows us to toggle the CPU's PCI-Express root complex between PCI-Express 1.0, 2.0, and 3.0 modes. To modify the number of lanes available to the GPU, we used common plastic adhesive tape."

    On a board that only supports up to PCi-E 1.1 or less, you're unlikely to be able to run any HD7000 series card.
  2. For the most recent discussion on PCI-E 3.0 cards and their backwards compatibility, see this:

    http://www.overclock.net/a/the-final-answer-to-the-controversial-pcie-x16-version-compatibility
  3. Thanks for the quick reply mate! tbh I wasn't really looking at HD7000 series cards all that much anyway, but thats good to know. I've been eyeballing a couple good deals on HD 6850s and will probably pull the trigger on one, unless I decide to save another $90 and get a EVGA GTX 660 SuperClocked.
  4. NveedEverywhere said:
    Thanks for the quick reply mate! tbh I wasn't really looking at HD7000 series cards all that much anyway, but thats good to know. I've been eyeballing a couple good deals on HD 6850s and will probably pull the trigger on one, unless I decide to save another $90 and get a EVGA GTX 660 SuperClocked.


    No problemo! My inclination would be to save up a bit for the GTX660. There are some discounts once in a while for the GTX660 series, but if you wanted more performance for your dollar, the newly introduced GTX659 TI "BOOST" edition is also really good.
  5. That GTX650Ti Boost looks nice! I think I might actually get that. BTW, I'm curious about your 490, what are your specs and what do you use it for?
  6. NveedEverywhere said:
    That GTX650Ti Boost looks nice! I think I might actually get that. BTW, I'm curious about your 490, what are your specs and what do you use it for?


    My 490 has 2x Xeon 5160 Dual Core CPUs (4 cores total) at 3.00 Ghz, 1333 FSB, 8GB of RAM. It currently has only a 250GB Samsung HDD. Originally it had a Nvidia Quadro video card (equivalent to something like an old FX5600, I think). It currently has an AMD/ATI HD 4770.

    The machine was a computational research machine. I did use it that way, mostly to run simulations. It also doubles nicely as a casual gaming computer. However, it isn't seeing much duty these days, and I'm contemplating giving it away to other researchers soon.
  7. Hello , I have a Precision 490 , 2x Xe 5320 quad's , 6 GB DDR2 667 ,SAS+146gb hdd and a Radeon HD 7750 for a while now, works fine, no problems whatsoever , I bought the card because it has low TDP and low consumption (lower that the old Quadro FX550) . Usually use the sistem in heavy web browsing and playing STO(trek) , the problem is , system runs better under win8 (especially in games) than win7. Win8 when it crashes it's unrecoverable (so switched back to win7 after 6 months , it's more stable).So see test , calculate PCI 1.1 = 55W or something like that + the PSU cable's you attach to VCard , se max consumption in charts and that's about it.The wearied part is I don't really know why my memories are not seen as ECC REG.... in PCwizard... and are under clocked (5:4) however the CPU dose go to 1.6 when IDLE...
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