Notice ATX MB riser card installation If you are using a full size ATX motherboard, please make sure the PCI-E card is on the 6th slot of the PCI slot in order to install the riser card correctly. Micro ATX MB riser card installation (Optional) If you are using a Micro ATX motherboard, an optional upgrade kit A2423 is offered to easily install to your system. A2423 upgrade kit(optional): the kit contains PCI-E riser card and PCI riser card.