We measured the noise from our testing participants in the entire supported speed range of their fans following the methodology described above. The results are summed up on the following graph:
Despite the fact that the noise curve of the Zalman CNPS11X Performa is very close to the noise curve of the Thermalright HR-02 Macho cooler, we have to point out that its fan was unstable and was occasionally howling at different speeds, which you can clearly see from the non-linear shape of the graph. The fan howls in its entire rotation speed range: louder at one speed and quieter at another, but this howling is constant and never ending. We can’t call it acoustically comfortable even at the lowest rotation speed. It is a serious flaw for the new cooler and may be a determinative factor for many potential buyers.
Unfortunately, Zalman CNPS11X Performa didn’t impress us with its superior efficiency and low level of noise. For the most part, it has only three advantages: small weight, low price and universal design combined with super-easy installation. However, these features are definitely not enough to guarantee marketing success for this product in the overwhelming versatility of quality choices available today. To win a contemporary cooler has to deliver good efficiency at a low level of noise, and to our regret Zalman CNPS11X Performa doesn’t have it. The cooler heatsink base is in desperate need of improvement and possibly implementation of advanced W-DTH (Whole-Direct Touch Heatpipe) technology without aluminum inserts between the heatpipes, just like by the flagship Zalman CNPS12X. It also needs a fifth heatpipe and could use a quieter fan. In this case Zalman CNPS11X Performa could become really nice. And in the meanwhile it is just a lightweight and universal mainstream product.