Heatsinks

A heatsink moves heat away from a component without a fan, using surface area alone. In a modern PC the part that most often needs one is the M.2 SSD.

Fast NVMe drives get hot under sustained load, and when they exceed their thermal limit they throttle — deliberately slowing to protect themselves. The symptom is a drive that starts a large file transfer quickly and then drops to a fraction of its speed part-way through, which people often mistake for a faulty drive.

Whether you need one depends on the drive. PCIe 5.0 drives need a heatsink, without exception. PCIe 4.0 drives benefit under sustained work and are usually fine for everyday use. PCIe 3.0 drives rarely need one.

Check first whether your motherboard already includes M.2 heatsinks — most current boards do, and fitting a second one on top achieves nothing. Also check clearance: a tall heatsink can foul a graphics card sitting in the slot above.

Apply the supplied thermal pad between drive and heatsink; the pad is what makes the contact work.