The NH-D15S is an asymmetrical single fan version of the NH-D15 that has been tailored to provide superior RAM and PCIe compatibility. In particular, the NH-D15S differs from the NH-D15 in the following regards:
- Asymmetrical design: While both coolers are 150mm wide, the NH-D15S is off-set towards the top edge of the motherboard and thus provides more clearance towards the PCIe slot.
- RAM clearance: While the front fan of the NH-D15 overhangs the RAM slots on many motherboards, the single fan NH-D15S provides 65mm clearance for tall RAM modules on all compatible sockets.
- Total height: While the front fan of the NH-D15 must be installed slightly higher in order to provide sufficient clearance for standard height (32mm) RAM modules, the single center fan of the NH-D15S can be installed lower on the fin stack. As a result, the total height of the NH-D15 including fans is 168mm whereas the total height of the NH-D15S including its single center fan is only 160mm.
- Performance: While the base performance of the NH-D15 and NH-D15S heatsinks are identical, the dual fan configuration of the NH-D15 can provide 1-3°C better performance. Users who have sufficient room can also upgrade the NH-D15S with either a 120mm (e.g. NF-A12x25 PWM) or round 140mm (e.g. NF-A15 PWM) fan on the front fin stack in order to achieve the same performance levels as the NH-D15. The fan clips for installing a second fan are included with the NH-D15S.