the IDE specification for 40 wire cables are such that the data transfer caps a 66MB/s Theoretical. 80 wire cables (which just ground each data cable) have Theoretical caps of up to 133MB/s. IDE drives made during the days of the Xbox were already beyond that (UMDA66) but just barely. These days almost any brand name laptop drive even can completely saturate a UMDA133 bus however. I've no idea what the Xbox actually supports in terms of IDE specification but the Nvidia MCP southbridges of the day supported UMDA100 .
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Board startup date: April 23, 2017 12:45:48