Symptoms
- Card (sound card, capture card, additional GPU, etc.) isn't detected by the system
- Card works in one PCIe slot but not another
- Device Manager shows the card with an error or doesn't list it at all
- Problem occurs right after installing the card
Likely causes
- CommonCard not fully seated in the slotPCIe cards need to click firmly into place, similar to RAM.
- CommonSlot bandwidth shared with or disabled by an M.2 driveMany motherboards disable certain PCIe slots when specific M.2 slots are populated.
- PossibleSlot requires a BIOS setting change to be enabled or set to the right modeSome boards default secondary slots to disabled or a different mode.
- PossibleInsufficient power for the card if it requires supplementary powerHigher-power cards need their own power connector, similar to graphics cards.
- PossibleFaulty card or slotTesting in a different slot or system isolates the true cause.
What to do
- Power down and reseat the card fully in its slot.
- Check the motherboard manual for any notes about slot sharing with M.2 or other slots.
- Try the card in a different PCIe slot if the motherboard has more than one of the right size.
- Check BIOS for any settings related to that specific slot needing to be enabled.
- Confirm the card has any required supplementary power connected if applicable.
- Test the card in a different computer, or a different card in this slot, to isolate whether it's the card or the slot.
Tools and parts
- Screwdriver
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.