Take a look at how much stricter the temperature and airflow requirements are for Intel&#x27;s 2.5&quot; U.2 drives compared to their add-in card counterparts. (And note that the U.2 drives are twice as thick as most SATA drives.)<p>M.2 has almost no place in the server market. U.2 does and will for the foreseeable future, but I&#x27;m not sure that it can serve the high-performance segment for long. It&#x27;s not clear whether it will reach the limits on capacity, heat, or link speed first, but all of those limits are clearly much closer than for add-in cards.