Noctua has tested over 100 PC cases to verify the cooler‑height limits that manufacturers list. The results show that 56 cases deviate from their posted specifications, with most offering more space than advertised.

Measured differences range from 3.5 mm less than claimed to as much as 10 mm extra. This variation means many buyers actually have more headroom than the case manuals suggest.

For example, the ASUS Prime AP201 advertises 170 mm of cooler clearance but real measurements show only 168.3 mm. The Lian Li B4‑m claims 168 mm yet measures 164.5 mm, making Noctua’s NH‑D15 G2 incompatible with either case.

In cases where the headroom is less than expected, users cannot shift front fans to increase RAM clearance, forcing the use of 32 mm tall kits for the NH‑D15 G2. Positive deviations are found in Corsair’s 5000 D, 4000 D and Frame 4000 D, and Thermaltake’s TR100, giving buyers up to 10 mm extra space. As Noctua expands testing, more entries will appear, helping buyers make informed choices.