Huge, aftermarket air coolers can have their drawbacks. For example, Noctua's NH-D15 and NH-C14 both block the first PCIe slot on most motherboards, a problem the company seeks to correct with its new NH-D15S and NH-C14S. The updated coolers have offset designs that should leave the first expansion slot unobstructed on most mobos.
The NH-D15S is a version of the dual-tower NH-D15 powered by a single NF-A15 140-mm fan. In addition to its offset towers, the D15S features cut-outs in the fins at its base to maximize RAM clearance—DIMMs with heat spreaders up to 2.6" (65 mm) tall can fit underneath. If RAM clearance isn't a concern, Noctua includes hardware to mount a second 120-mm or 140-mm fan on the D15S' front face. The D15S is 6.5" (165 mm) tall with a fan installed.
For those with cases that can't accept the NH-D15S' towering height, the NH-C14S might be the answer. The C14S cocks the radiator at 90°, and it can be configured in three ways: with the fan up top to clear tall RAM heatsinks, with the fan slung under the radiator for low-profile operation, or (optionally) with dual fans for maximum cooling power. Installing a fan on top makes the NH-C14S 5.6" (142 mm) tall, while slipping one underneath lowers the height to 4.5" (115 mm).
The NH-C14S will be available "shortly" with a suggested price of $74.90, while the NH-D15S is scheduled to ship in June with a $79.90 sticker. Both coolers come with a tube of thermal paste, universal mounting brackets for Intel and AMD CPU sockets, and six-year warranties.