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 difference in the displayed delta temperatures are not important for our PBO testing as the clock speed and cooling power achieved are more important metrics.
A very strong start is made by the dual fan Fera 5 in our PBO test. Managing to cool 212W of package power is excellent and actually beats out the more expensive be quiet! Shadow Rock Slim 2 as a mid-range reference point.
Impressively, this saw our 5950X test CPU running at 4.31GHz all-core which was at least a couple of hundred MHz higher than what we saw from other mid-range level coolers.
This is a very good start by SilentiumPC.
If you are interested in stock results, the Fera 5 Dual runs at 32-33C above ambient which is – once again – about the same as the be quiet! Shadow Rock Slim 2.
The 5950X quoted all-core frequency here was around 3.85-3.86GHz which is marginally higher than the Zalman and be quiet! 135mm models, albeit by an insignificant difference.