Noise levels were similar for both coolers when the Core i7 processor was idle, but there was a significant temperature difference. Intel’s retail cooler never reaches less than 48°C at its stock idle speed (133 MHz x 12 = 1,600 MHz) or less than 58°C at its overclocked idle speed (185 MHz x 12 = 2,220 MHz). In contrast, the Zalman CNPS 10X keeps the core at 39°C when idle at stock speed and at 42°C overclocked.
Let’s look at the processor peak load temperatures. Intel’s cooler results in a constant 68°C when the 2.66 GHz Core i7-920 runs at full load on all four cores. The same scenario results in a 62°C CPU temperature using the Zalman CNPS 10X.
But it’s the overclocked temperatures that demonstrate most impressively how well the Zalman cooler performs (or how poorly the retail cooler copes with extra heat). The temperature level ranges between 75-79°C for the CNPS 10X, depending on the fan speed, while the Intel cooler is incapable of addressing the additional heat, and the CPU runs at 94°C.
Needless to say, the Zalman cooler we used enables additional overclocking margins by cooling down the 3.7 GHz Core i7 by roughly 20°C.