Do Water Blocks Improve GPU Performance

Sep 21, 2019 | 5-Min. Read

Atila Gobor

AMD Radeon Vega GPUs might not be the newest on the market, but they are a great sample to use to revisit a fairly common question. Will liquid cooling improve your GPU performance? Thermal throttling is a real thing and thermal sensors are being implemented in all modern CPU and GPU to prevent any damage to the chip in case of overheating. A safety feature like this is mandatory since coolers can fail, fans can get blocked, heatsinks can be incorrectly mounted by user error etc. This topic got very hot (pun intended) back in 2001 when Tom’s Hardware published a video on what happens to CPUs when the cooler is removed. Thermal diode implementation and thermal safety became a very serious and mandatory thing from that point on. Today, all CPUs and GPUs are equipped with thermal sensors and sophisticated power management systems which limit the performance of the processing unit in case the thermal limit is hit.

These thermal safety features can also impact the upper-performance limit of a CPU or a GPU. This “phenomena” is more explicit in the case of GPUs where manufacturers are implementing a thing called “boost-frequency”. The boost feature raises the clock frequency if the GPU senses it has efficient cooling and headroom for additional performance to be squeezed out of it. It is quite common that reference design, blower type coolers often struggle with cooling, hence the reason for vendors developing huge custom cooling solutions with intricate heat-pipe systems and multiple fans… which still can be loud. But for those who want more, there is always the solution of liquid cooling. And of course, who can resist that single slot slimness that some full cover water blocks can offer?

So we are going to revisit the subject of efficient cooling with an example of a full cover water block and its effect on the performance of a high-end desktop graphics card. So to get you up to speed really quick, we will just show you some 4K and 8K Unigine Superposition  benchmark results with an air cooled AMD Radeon RX Vega 64 8GB and benchmark results while liquid cooling and overclocking the same GPU. First off, the 4K test results.

Our test rig was placed on an open bench table, so the air cooled GPU was perfectly ventilated.

Our water cooling gear consisted of:
– EK-CoolStream XE 360 radiator
– 3x EK-Vardar F2-120 Fans
– EK-XRES 140 Revo D5 pump+reservoir combo
– EK-FC Radeon Vega GPU water block


EK-FC Radeon Vega water block Flir thermal image with GPU under load


Unigine Superposition 4K benchmark – air cooled on the left, Unigine Superposition 4K benchmark – water cooled and overclocked on the right

While running the 4K benchmark test, the air cooled GPU hit 80°C at stock clocks with the fan running at 100%, while the maximum temperature of the liquid cooled and overclocked AMD Radeon RX Vega 64 was only 39°C. Quite a significant difference right? The maximum core clock with air cooling hanged around in the 1400-is while with liquid cooling, the overclocked GPU could run above 1600MHz while not showing any signs of throttling. How does this translate to real-life? Its 20% more performance in 4K results and much less noise. Moving on to some 8K results.


Unigine Superposition 8K benchmark – air cooled on the left, Unigine Superposition 8K benchmark – water cooled and overclocked on the right

Nothing new happened with the 8K benchmarks. The air cooled GPU hit 80°C again, while the water cooled GPU was half that “hot”. Again, the liquid cooled GPU did not have to run the fans on 100% and yet it remained cool and the stable overclock brought a 20% increase in performance. But let’s not just stop here.

Both of the overclock results were achieved with a little added tweaking as well. Both 4K and 8K OC scores were done by undervolting the GPU a little bit. By optimizing your overclock, you can gain even more performance. For you to fine tune your GPU, you will need the following software:
–  Radeon WattMan
–  WattTool (0.92 or newer)

By undervolting the GPU and increasing the power limit, you can hit a sweet spot that will reduce power consumption, lower the core temperature and bring more performance. In the table below you can see various scenarios while fiddling with these parameters.

Important notice for Radeon Vega Frontier Edition owners overclocking through WattTool: You need to set each of the lower states (P1, P2, P3, P4, P5) to different voltage levels, otherwise the card may not return to lower power state on idle. P6 and P7 state may be set to the same voltage. For the time being, do not set memory frequency through WattTool as it is missing a power state. Vega RX series owners should use AMD Wattman instead.

Overclocking is still a little bit of lottery and the final result will also depend on the sample you have, but with the help of this table, you can know in which direction you should be going with your overclock optimization. In the end, we must mention it again that the air cooled GPU worked on an open bench table, which means that in some enclosures, things can even be worse. With the help of liquid cooling and a full cover water block, the GPU can easily be overclocked and it can maintain the high core frequency without and performance drops or thermal throttling. But don’t just take our word for granted, you can check out JayzTwoCents video and his experience with adding a water block to his AMD Radeon RX Vega graphics card.