For cooling performance testing I do a whole series of tests. I run three different load types both at 100% fan speed and with the stock fan profile our motherboard provides. I do this across three different CPUs to get an idea of what to expect depending on what you are using the Pure Loop on. This includes the 3900X, 3600X, and then the 3400G. I start with the AIDA64 Stress Test using the FPU load which is the most demanding. Because Ryzen CPUs like to cap at a specific temperature and downclock for these extra demanding workloads I also keep track of the clock speeds. At 100% fan speed the Pure Loop did well, competing with the larger 280mm Castle cooler with the 3900X. It did come in a little lower in the stock profile test, even compared to the H100i however. The 3600X looked similar with it matching both of the AIOs with the stock fan profile but being a degree lower at 100% fan speed. Then for the 3400G, it clocked higher on both tests even with the temperatures being the same and a degree higher when it came to the stock fan profile test.
Next, I tested using a real-world demanding workload with Blender. For the 3900X the stock fan profile was a little weak in performance, coming in at a lower clock speed than the other AIOs and one degree higher than the H100i. The temperature at 100% fan speed was better but the clock speed was again a hair lower. For the 3600X its temperature was higher, but it matched the clock speed of the other coolers at stock and 100% perfectly. Then with the 3400G, the stock fan profile had the temperatures higher, and the clock speeds down with what the air coolers were seeing but with the fans cranked up it was the fastest for clock speed.
The last round of testing to me is the most realistic when it comes to normal workloads and gaming. AIDA64’s Stress Tests CPU workload which puts the CPU under 100% load on a non floating point level. Here the heat generation isn’t so bad that we need to keep track of clock speeds. With the 3900X the Prue Loop matched the temperatures of the two other AIOs with the stock fan speeds and was two degrees lower than the H100i at 100% fan speed and even 1 degree under the larger Castle 280EX. With the 3600X it was a degree higher on the stock profile then all three had the same result at 100% fan speed. Then for the 3400G, the stock profile result was a lot warmer than the other AIOs but the 100% fan speed results have it lower than the H100i by two degrees and just one over the larger 280mm Castle cooler.