Maybe not even that (4.0 vs 5.0 etc) but some of these PCI-express adapaters...
Something like this could actually start generating a measureable amount of heat with 4 NVMe's smashed tightly together like that. Finding a quad adapter was seconds finding an 8 drive adapter too a bit more effort but it already has a heatsink/fan as part of the package.
A card like this one with swapped for a water block on top is actually starting to make a lot of sense for some applications. Not for single drives but for clusters/arrays of drives.
Aplicata Quad M.2 NVMe SSD PCIe x8 Adapter : Amazon.ca: Electronics
Aplicata Quad M.2 NVMe SSD PCIe x8 Adapter : Amazon.ca: Electronics
www.amazon.ca
Highpoint SSD7540 NVMe 8-Port M.2/U.2 Industry Fastest-Performance/Comprehensive Selection Capable of Supporting Over 100TB On a Single Controller! : Amazon.ca: Electronics
Highpoint SSD7540 NVMe 8-Port M.2/U.2 Industry Fastest-Performance/Comprehensive Selection Capable of Supporting Over 100TB On a Single Controller! : Amazon.ca: Electronics
www.amazon.ca