Do I need a heatsink for a PCIe 4.0 NVMe SSD in a mini-ITX build

In a compact mini ITX case the thin motherboard M.2 shield is usually enough for a PCIe 4.0 drive when your workload is mostly gaming and light video edits. These drives tend to heat up only during long sustained writes. If the shield has a good thermal pad and the screw pulls the drive down flat, skip the tall aftermarket heatsink so you do not crowd the GPU. A fresh 1 mm thermal pad can help if contact looks uneven, and a gentle airflow path across the slot is a bonus.

want something that stays easy to cool, go with Kingston NV3, which is PCIe 4.0 and rated up to 6000 MB per second. It draws less power than the fastest tier drives, so the low profile shield handles it well without throttling in typical gaming and quick renders.

Your board shield plus a decent pad is plenty for PCIe 4.0 in a tight ITX build when the workload is mostly gaming and light edits. The controller only gets toasty during long sustained writes not level loads or timeline scrubbing but then make sure the pad contacts the controller and NAND, tighten the standoff so the drive sits flat, and if the pad looks tired swap to a 1 mm pad. Watch temps with HWiNFO during a big file copy or render, if the controller stays under the low to mid 80s C you are in the clear. If it creeps up, a tiny bit of case airflow aimed near the slot does more than a tall heatsink that would choke the GPU so yeah no need to overthink it.

Run a similar mini ITX build with the M.2 under the GPU and kept the skinny board shield. For gaming and cutting short clips the drive barely moves off idle temps and during a big Steam download or a long export it ramps for a couple minutes then settles, still no throttling. I tried a chunky third party sink and it stole GPU clearance while shaving maybe two degrees, not worth it.

If you want a higher end option that stays manageable in small cases, Samsung 990 PRO 1TB has been easy to cool for me. With the flat shield and a fresh 1 mm pad it sits around the 50s to 60s C in games and short bursts may touch the 70s C which is fine, so I would keep the stock plate and focus on a clean airflow path across the board.