Keep the memory accessible without raising a front fan
Document findingNH-U12S redux + Ryzen 7 7800X3D + B650 GAMING PLUS WIFI + 4000D AIRFLOW
The complete cooler is 158 mm tall against a 170 mm case limit: 12 mm nominal allowance. Noctua states that this slim design does not overhang RAM, and lists the cooler for the selected CPU and motherboard.
Build decision: Use the standard single-fan arrangement. The 35 mm memory remains accessible without raising the cooler fan toward the case side panel.
Still to check: Check the mounting parts in the purchased box and verify temperatures and fan noise with your workload. This smaller tower is not claimed to match dual-tower cooling, and the complete assembly has not been physically tested.
Document review:- Noctua NH-U12S redux specificationsMechanical specifications: height with fan 158 mm; AM5 socket support
- Noctua NH-U12S redux features100% RAM compatibility: 45 mm fin depth does not overhang the memory slots
- Noctua Ryzen 7 7800X3D compatibilityExact NH-U12S redux row: compatible mounting; NSPR 129; manufacturer performance class
- Noctua MSI B650 Gaming Plus WIFI compatibilityExact NH-U12S redux row: compatible mounting with no listed restriction
- CORSAIR 4000D / 4000D AIRFLOW manualEnglish page 1 (PDF page 3): Case specifications — Maximum CPU height, 170 mm
Images are for reference only. Refer to the linked store for actual product images.