As also shown in FIG. 1, chassis 100 may house information handling resources, including without limitation a motherboard 104 and a riser card assembly 106. Riser card assembly 106 may communicatively couple to motherboard 104 via a cable 108 terminated with a connector 110, wherein such connector 110 may be configured to couple to a corresponding connector 112 of motherboard 104. Further, riser card assembly 106 may include a receptacle connector 114 for mechanically and communicatively coupling an expansion card to riser card assembly 106, in order to communicatively couple such expansion card to motherboard 104.

As further shown in FIG. 1, motherboard 104 may include one or more mechanical retention posts 116, wherein each mechanical retention post 116 is configured to mechanically engage with a corresponding mechanical feature of riser card assembly 106 in order to mechanically retain riser card assembly 106 to motherboard 104. In some embodiments, a size, a shape, a placement, and/or other features of each mechanical retention post 116 may be defined by a standard, such as the Open Compute Project (OCP), for example. In particular, the mechanical feature of riser card assembly 106 may include a detent assembly as described in greater detail in FIGS. 2 through 4B below, and which is not visible in FIG. 1 as such detent assembly may be located beneath riser card assembly 106 in the perspective shown.