Thermal Performance

Testing the block for thermal performance was fairly simple, once you realize that you have to measure VRM temperatures manually. As such, I installed an Omega NTC type thermistor on VRM 1 and connected it to an external display for a VRM temperature readout. TechPowerUp GPU-Z was used to monitor GPU core temperatures. The GPU was overclocked to 2 GHz, although with how GPU Boost 3.0 works it did vary by +/- 1 clock bin (13 MHz). Similarly, with core voltage being near impossible to set manually and fix at that point, it is best to compare the results below within the data set and not with other reviews elsewhere. For what it is worth, 1.20 V was set at Vcore using EVGA Precision-X.

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 since not all blocks come with TIM included, 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 60 minute Unigine Heaven 4.0 run was done, and temperatures were monitored until a steady state was reached, after which they were recorded. A delta T of GPU core/VRM and loop temperatures 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.


When there is just over 3 °C of difference between all the blocks in terms of GPU core cooling, you know things are hard to distinguish. The Phanteks Glacier GTX 1080 falls in the lower half of the table here, but only just and not by much. A lot of this has to do with not cramming in more surface area over the core in the cold plate, which did aid in flow restriction as we saw on the previous page. Also note that I had no backplate here, which may have helped thermal performance further.

When it comes to VRM cooling, things are a lot more spread out. Here, the Phanteks block performs more admirably and well within what the power delivery on the reference GTX 1080 PCB needs. Overall, a good job here!