Intel 820E Manual De Usuario

72  

Design 

Guide 

Environmental testing and field reports indicate that, without proper retention, AGP cards and AGP 
In-Line Memory Module (AIMM) cards may come unseated during system shipping and handling. In 
order to prevent the disengagement of AGP cards and AIMM modules, Intel recommends that AGP-
based platforms use the AGP retention mechanism (RM).  

The AGP RM is a mounting bracket used to properly locate the card with respect to the chassis and to 
assist with card retention. The AGP RM is available in two different handle orientations: left-handed (see 
Figure 40) and right-handed. Most system boards accommodate the left-handed AGP RM. Because the 
manufacturing capacity is greater for the left-handed RM, Intel recommends that customers design into 
their systems the left-handed AGP RM (Figure 41). The right-handed AGP RM is identical to the left-
handed AGP RM, except for the position of the actuation handle, which is located on the same end as in 
the primary design, but extends from the opposite side, parallel to the longitudinal axis of the part. Figure 
41 details the keep-out information for the left-handed AGP RM. Use this information to ensure that your 
motherboard design leaves adequate space for RM installation. 

The AGP interconnect design requires that the AGP card be retained so as to limit card back-out within 
the AGP connector to 0.99 mm (0.039 in.) max. For this reason, new cards should have an additional 
mechanical keying tab notch, which provides an anchor point on the AGP card for interfacing with the 
AGP RM. The RM’s round peg engages with the AGP or AIMM card’s retention tab, thereby preventing 
the card from disengaging during dynamic loading. The additional notch in the mechanical keying tab is 
required for 1.5 V AGP cards and is recommended for the new 3.3 V AGP cards.