Tailored to provide superior RAM and PCIe compatibility, the NH-D15S is an asymmetrical single fan version of Noctua's award-winning flagship model, the NH-D15. Thanks to its asymmetrical design, the NH-D15S clears the top PCIe slot on most ATX and ATX motherboards. At the same time, the single fan setup and recessed lower fins guarantee 100% RAM compatibility with memory modules of up to 65mm height. Users who have sufficient room can also upgrade the cooler with either a 120mm or round 140mm fan on the front fin stack for further improved performance in dual fan mode. Topped off with the trusted, pro-grade SecuFirm2 multi-socket mounting system, Noctua's proven NT-H1 thermal compound and full 6 years manufacturer's warranty, the NH-D15S forms a complete premium quality solution that combines dual tower efficiency with excellent compatibility and flexible upgrade options.