Let’s start by looking at Precision Boost Overdrive test results. With 90C the maximum target temperature for PBO, we are looking at how the cooler achieves the balance between lower temperature operation and higher PBO clock speeds. Higher clocks with lower temperatures are better. But one cooler may run at slightly higher temperatures than another, albeit with higher clock speeds, so look out for that.
In essence, this test is showing us how far the cooler can be pushed while keeping a sensible 90C maximum. Or whether there is more room for pushing clocks and power delivery beyond the PBO limits while still sticking to a 90C target.
Firstly, it is critical to note that small differences in the displayed delta temperatures are not important for our PBO testing as the clock speed and cooling power achieved are more important metrics.
Zalman’s CNPS10X Performa Black manages to cool 204W of CPU package power from our Ryzen 9 5950X. This translates into an average CPU clock speed of 4260MHz. By comparison, the slightly more expensive and marginally lower noise be quiet! Shadow Rock 3 tolerates 202W of cooling that translates into 4230MHz average clock speed.
Between the two, Zalman’s option is a slightly higher performer and allows the chip to deliver marginally higher clock speeds. In fact, Zalman does a decent job at closing the gap to some of the bigger dual-tower coolers such as the Arctic Freezer 50. And the budget Arctic Freezer 33 eSports One (which is very similar to the current Freezer 34 model that is around £30 in the UK) is comfortably outperformed. Zalman’s slightly more expensive cooler offers more than 300MHz higher clock speed capability for our Ryzen processor.
That is a strong victory for Zalman.
And if you are interested in stock results, the Zalman CNPS10X Performa Black recorded a temperature delta of 33-34C for 128W package power cooled.
That is similar to the physically larger and more expensive Arctic Freezer 50 in terms of temperature. Though the Zalman cooler did deliver a slightly lower average clock speed of around 3.85GHz versus around 3.87GHz.