PCI-E x8 in x16 Slot

  1. Posts : 366
    Windows 10 Pro x64

    PCI-E x8 in x16 Slot

    From what I have read, it seems that one can use a PCI-E x8 card in a x16 slot. Im looking to install a PCI-E SAS card in my desktop. Nearly all of the ones Ive seen so far seem to use a x8 interface but my desktop has only 2 x16 slots, 1 x4 slot and 2 x1 slots. Before I pull the trigger and get this card, I want to be sure that you can use the smaller card in the larger slot. Everything Ive seen so far seems to suggest it will work without an issue.
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  2. TV2
    Posts : 2,018
    W10 Pro 20H2

    Yes, it will work. The slots are downward compatible!
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  3. Posts : 26,397
    Win11 Pro, Win10 Pro N, Win10 Home, Windows 8.1 Pro, Ubuntu

    The only thing is it will effect bandwidth, here is an example from my PDF manual:
    PCI-E x8 in x16 Slot-2017_04_02_17_33_541.png
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  4. Posts : 366
    Windows 10 Pro x64
    Thread Starter

    Thank you both for your input. I want to turn my desktop into a file server for my house and would like to use some higher end SAS drives to do so. It looks like there are a few SAS cards on eBay for a good price.
      My Computers

  5. Posts : 3,257
    Windows 10 Pro

    Cliff S said:
    The only thing is it will effect bandwidth, here is an example from my PDF manual:
    There are a total of 20 PCIe lanes available on your motherboard, so you have to be careful. Depending on chipset, this will vary. For instance the Z270 has 24 lanes available, but the H270 has only 20.

    If your chipset has 24 lanes, then you can run an x16 and an x8 at full speed, but if you have only 20 then your x8 will run at x4.
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  6. Posts : 1,366
    Windows 10 Pro x64

    I wouldn't waste the time and money on SAS drives for a home file server. Just get NAS-rated SATA drives, such as the Western Digital Red series.
      My Computer


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