I was wondering what performance drops I'd get, by running a second Graphics card on a low bandwidth PCIex16 port (running at x4).

The second card (an "ASUS GeForce 210" (yeah pathetic)) is there for running an extra couple of screens for business (those screens would be disabled when gaming).

Would my more powerful card, on the full bandwidth slot be slowed (due to the others slowness)? How much would the second Graphics Card be slowed by the lower bandwidth?

If I'm unclear, tell me, and I'll try to rephrase. Thanks in advance.

  • AFAIK (and through various tests and benchmarks I have seen) current-gen GPUs don't even max out a PCIE 3.0 x4 connection, so you should be good. It only matters when doing massive I/O tasks (some games do this while others don't). If you can, just test it out.
    – GiantTree
    Commented Sep 28, 2016 at 20:02

1 Answer 1


It all depends on both your CPU and GPUs.

Your CPU has a fixed number of PCIe lanes. If the x4 graphics card leaves less than 16 PCIe lanes to your main graphics card, then you might or might not suffer a performance drop, depending on how I/O intensive your GPUs are.

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