I've been given an old(ish) graphics card, with the make and model not listed clearly, or at all, on the card. Or perhaps they are, but are covered by the heatsink. Assume also that I don't have access to a machine to play with, into which I could check whether the card fits.

How can I tell, by only looking at the card itself and without trying to insert it anywhere, whether it's a PCIe card or an AGP one? I remember the physical slot interface is somewhat similar with both of them having an L-shaped latch towards the back, which makes it relatively easy to mistake them with each other (as opposed to PCI cards which don't have this latch).


Consider this image of the slot part of two cards, a PCIe 16x graphics card (bottom) and an AGP 8x graphics card (top):

enter image description here

They have the following distinctive features:

  • L-latch length: AGP cards' back-L "latch" extends all the way down to the same level as the connector pins; with PCIe, the latch is shorter.
  • Pin pattern: The AGP card has a sort of a zig-zag pattern where subsequent pins are at different heights; PCIe pins are all parallel to each other.
  • Position of slit: The PCIe connector pins are split by a slit in the PCB close to the front of the card, while the AGP card's similar slit is much further to the back (beyond the half-point).


  • You can't trust other differences, like the AGP card not having pins on the L-latch, since some PCIe cards don't have them either (I think).
  • Even if you're sure you've correctly identified the type of card, be very careful when inserting it into the socket and refrain from applying more than a little bit of pressure to avoid damaging the hardware.
  • 1
    Isn't AGP slot also offset differently with respect to the mounting bracket/case knockout? – Yorik Jul 11 '18 at 17:01

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