Testing:
To test the thermal performance of the
Zalman CNPS9900 LED CPU cooler, the idle and load temperatures were monitored while running
OCCT 2.0.1. The idle condition was established with the system sitting at the Window's desktop with only OCCT open for a period of one hour. The load condition was established by running OCCT for a period of one hour. Among other things, OCCT monitors individual CPU core temperatures, and these readings were used for all phases of testing.
For comparison purposes, the CNPS9900 LED CPU cooler was tested head-to-head with four other coolers. The stock Intel cooler, the
OCZ Technology Vendetta, the
OCZ Technology Vendetta II, and the
Noctua NH-U12P. In terms of size, the Zalman cooler is bigger than the stock cooler and the original Vendetta, an just about the same size as the Vendetta 2 and the NH-U12P (although these two are square cut coolers and appear much bigger). All of the coolers used the Zalman Super Thermal Grease during testing.
The four reference coolers were all run with their fans at full speed, while the Zalman cooler was run with the fan at three different speeds. The first test was at full speed, which was found to be 2163RPM (an rather loud). Next, a fan speed controller was connected and I reduced the speed until the noise was noticeably quieter. This translated to a speed of 1662RPM. Finally, the fan speed was brought down as low as the fan speed controller could go, at which point the noise was very quiet (although not quite silent). This translated to a speed of 1028RPM.
The chart below details the results from all of the coolers achieved while maintaining an ambient temperature of 20 degrees Celsius.
The temperatures in the chart above are all acompanied by subjective labels to describe the noise produced. At our near full speed the CNPS9900 LED's fan was too loud, but the cooling performance was so impressive that some people might be willing to get used to it. It definitely isn't the loudest cooler of the bunch, and you only need to knock a few hundred RPM off in order to make it much quieter.
In order to the get the CNPS9900 LED to be about as quiet as the Noctua NH-U12P, the speed had to be cut to less than half of the default value. The NH-U12P did this with its low flow fan at full speed, and you will need your own fan controller and/or PWM capable motherboard to make it happen on the CNPS9900 LED. Of interest is that at this low speed/low noise setting, the temperature on each CPU core is now 3-5 degrees higher than the NH-U12P and 6-7 degrees higher than the CNPS9900 LED at full speed. The temperatures are definitely still quite safe, and still way better than what the stock Intel cooler was capable of!
