most of the NVMe backplanes I&#x27;ve seen give full &#x27;enterprise 2.5&quot; drive clearance to the thing, so if they are actually as thick as consumer SSDs, as most current SATA &#x27;enterprise SSD&#x27; are, there&#x27;s plenty of room for a heatsink without expanding the slot.   The supermicro chassis (and I&#x27;ve only explored the NVMe backplanes from supermicro) usually put a lot of effort into drawing air through the drives, so assuming you put in blanks and stuff, the airflow should be there, if the SSD are setup to take advantage of it.