For PCIE3 SSDS, Such as the 950 PRO, 960 PRO, 960 EVO, 970 PRO, 970 EVO, 970 EVO Plus, and the 980:
Please make sure your M.2 Port supports PCIE Gen 3 and is x4. Also, install the Samsung NVME driver.
For PCIE4 SSDS, Such as the 980 PRO and the 990 PRO:
Please make sure your M.2 Port supports PCIE Gen 4 and is x4. The PCIE4 NVME SSDs are backwards compatible with PCIE3 slots, but will only run at PCIE 3 Speeds. Also, if you have multiple NVME drives plugged in, most motherboards tend to share bandwidth across multiple M.2 ports, so you wont get full speeds with multiple drives connected.