To measure the CPU's temperature, we used the latest SpeedFan, which offers real time temperature monitoring and we created a graph of the temperature over time. After letting the processor cool down in idle mode, we fired up Prime95 and ran the In-place large FFT test to heat it up to its maximum level.

This is the graph of the temperature with the stock AMD fansink...

Stock AMD CPU cooler

... and this is the graph with the KestrelKing V fansink. You can see that there is almost 5°C degrees difference under high load.

KestrelKing V

The powerful fan of the KestrelKing VI fansink gives higher air flow and can reach even lower temperatures. Very good performance was observed, almost 10°C lower than the stock CPU cooler under high load.

KestrelKing VI

It should be noted that with no load (idle), the temperatures reported by SpeedFan is almost the same with all these coolers. But the KestrelKing V and the KestrelKing VI show their teeth under high CPU load. Also, the KestrelKing VI can increase its rotation speed up to 6000RPM, while the KestrelKing V fansink cannot. This gives the KestrelKing VI a big advantage over the KestrelKing V.

Overclocking

The default setting for the AMD64 3500+ is set to 2200GHz (200MHz HTT and x11 multiplier). We fooled around with the BIOS settings and we got the system running nicely at 2700 GHz (ASUS A8N-SLI Deluxe motherboard). At that speed, the system was able to boot and when running Prime95, which is very sensitive and hence ideal for identifying errors, it reported all calculations correct.

SpeedFan again gave us real time temperature monitoring throughout the CPU stress test.

KestrelKing V

KestrelKing VI

The idle temperature was 40°C for both of these coolers, but the KestrelKing V cooler reached 55°C under heavy load. In other words, the performance of the KestrelKing V cooler with the system overclocked is similar to the performance of the stock cooler under nominal clock speeds. With the KestrelKing VI cooler, the CPU temperature was even lower, at 49°C.