Thermal PerformanceGiven this is an LGA 115x-only CPU block, I used my Core I7-4770K test rig paired with the Asus Maximus VI Formula motherboard and 2x 8 GB Corsair Dominator Platinum DDR3 RAM at 1866 MHz (CAS9-10-9-11). The CPU was overclocked to 4.7 GHz at 1.4 Vcore to provide as much heat to be dissipated away as reasonable possible while stable. A Swiftech MCP35x2 pump, an Aquaero 6 XT controller, and a Black Ice Nemesis GTX 480 radiator with Noiseblocker NB-eLoop B12-3 fans completed the loop. The GPU was not placed in the loop to make sure the only source of heat was the CPU and, thus, the CPU block itself. Average flow rate was set to 1 GPM, and calibrated in-line temperature sensors were used to measure coolant temperature.
Everything required was placed inside a hotbox, and the ambient temperature was set to 25 °C. Gelid GC-Extreme was used as the thermal paste of choice and cure time was taken into consideration. Five separate mounts/runs were done for statistical accuracy and to remove the chance of any mounting-related anomalies. For each run, a 90 minute Intel XTU stability test was performed. XTU is a stability test from HWBot that uses a custom preset of Prime 95 (no AVR), which ensured the load is uniform on each run. CPU core temperatures were measured using Aida64, and the average core temperature was recorded at the end of each run. A delta T of CPU core and loop temperature was thus calculated for each run, with an average delta T that was then obtained across all five runs. This way, the cooling solution is taken out of the picture. The effect of block orientation was also tested, and the best orientation was used for these runs, with the result shown below.
The blocks are a bit more spread out here in comparison to my i7-5960X test rig, with a ~4.5 °C difference between the average performance of each block in its best-performing orientation. Even so, it is a struggle to differentiate blocks from the last couple of years, and the Bykski FOUR is no exception. That said, it does manage to be in the top half of the table here, so thermal performance is quite decent and only 0.5 °C off the top performer as of the time of this review.