7.3.3. RX MAC Adapter Limitations
In the 40GE/50GE RX MAC client interface with enabled CRC passthrough, you may observe dropped frames with fewer than nine octets. When CRC passthrough is disabled, you may observe the dropped frames with fewer than 13 octets.
In the 100GE RX MAC Avalon ST client interface, if two frames received with frame starts less than 5 blocks apart, the first frame is dropped. A start is equivalent to the start of the frame. A block references a 64 bit encoded block, as defined in the IEEE 802.3 Clause 49 standard.
You can view the number of dropped frames by reading the statistics registers.