The latest samsung NVMe SSD has better heat dissipation, I have 2 installed with cheap aluminum heatsinks on Asus Strix Z270E: a windows 10 pro 960 evo PCIe 3.0x4 at 35 idle and 45 peak temp, while the windows 7 WD black 1st generation idles at 45 and peaks at 55 when loading system of it. This with video card installed vertically away from the mobo with open case (TT core P3) and no mobo supportive ventilation (except for the CPU 360mm TT radiator/fans).
Tested also 2x Samsung PM961 (OEM 960 evo) and they run cool as well, don't know about the new WD black 2nd generation or the Samsung 970 which one appears to have better heat dissipation.