The NH-L9i looks downright comical inside a large full tower like the CM Storm Stryker, but don't let the cooler's diminutive appearance fool you, as it is fully capable of keeping the i5-2500 within a safe thermal envelope. Idle temps hovered around 30 °C and opening up a typical daily suite of apps pushed things to 34 °C. Watching HD movies and playig process intensive games like Battlefield 3, Borderlands 2, and Far Cry 3 raised the bar to about 52 °C. For benchmarking purposes, we used Prime 95 to exert 100% load on the CPU at factory and overclocked speeds of 3.3GHz and 3.8GHz respectively. CPU core temperatures were recorded using Real Temp GT. As you can see from the results below, the NH-L9i doesn't do a particularly good job of fending off increasing temps on a 100% loaded CPU, but the rate of cooldown is admittedly impressive. Of course, the NH-L9i was not designed with gaming desktops in mind. In fact, the i5-2500's TDP of 95W exceeds the cooler's recommended TDP application of 65W, but it's good to know that this little guy can roll with the punches when pushed.
For idle testing, we booted up the system, allowed the CPU to stabilized at ~0% usage, and then tested for at least 10 minutes. Then we used RealTemp GT to record the CPU temperatures once the temperatures were stable. We tested two different conditions of the i5-2500, the first is completely stock and default settings of 3.3GHz, and the second is overclocked to 3.8GHz with AUTO voltage. The single temperature recorded was the average between the four cores.
The NH-L9i has absolutely no problem keeping up with the bigger coolers when our test setup is idling, and actually has a small advantage over its larger sibling the NH-L12, which is also classified as a low-profile cooler. This can probably be attributed to the higher RPM of the NH-L9i's tiny but effective NF-A9x14 PWM fan. Results were consistent between clock speeds of 3.3Ghz and 3.8GHz, with RealTemp GT recording an increase of only one degree. It's no surprise that the NH-L9i is able to maintain a ~30 °C temperature under virtually zero load, but that's not what you're anxious to see now is it?
Moving on to the main event, we see that the $49.99 NH-L9i is vastly outgunned by the heavyweight coolers. However, given that this is only the second mini-ITX compatible cooler that we have tested, it is important to keep in mind that the loads we are exerting on the CPU in this torture test are not likely to ever be encountered during the typical media playback routine of an HTPC. Add that a cooler like the 158mm tall Cooler Master TPC-812 comes with features like vertical vapor chamber technology and an MSRP of $69.99 and the performance/price ratio starts to make a little more sense. Load temperatures of 70 °C are respectable for a cooler of this size, but if you really want a cooler CPU while maintaining mini-ITX compatibility, the $69.99 NH-L12's 66mm height (with single fan arrangement) is a viable albeit expensive option.