The Noctua NH-L9i-17xx wins in 2 out of 3 comparable specs. Its biggest advantage is MSRP (44% better).
NH-D15S wins in 1 spec (TDP Rating: 285% better).
Recommendation
Choose NH-L9i-17xx if you want the best overall performance — especially msrp.
Choose NH-D15S if tdp rating matters more to you.
| Spec | NoctuaNH-D15S | NoctuaNH-L9i-17xx |
|---|---|---|
| Design | ||
| Type | Air Tower | Low Profile |
| Height | 165 mm | 37 mm |
| Performance | ||
| TDP Rating | 250W+285% | 65W |
| Fans | 1 | 1 |
| Fan Size | 140 mm | 92 mm |
| Acoustics | ||
| Noise Level | 24.6 dB(A) | 23.6 dB(A)−4% |
| Fan RPM |
| 300 - 1500 |
| 600 - 2500 |
| Compatibility | ||
| Sockets | AM2+, AM3+, FM2+, LGA2011-3, LGA2011, LGA2066, LGA1851, LGA1700, LGA1200, LGA1156, LGA1155, LGA1151, LGA1150, AM5, AM4, AM3, AM2, FM1, FM2 | LGA1851, LGA1700 |
| Price | ||
| MSRP | $80 | $45−44% |
| Release Date | Jan 2019 | Nov 2021 |