Temperatures, Clock Rates & Overclocking
Overclocking & Undervolting
Conventional overclocking through a higher power limit and more aggressive clock rate is a dead-end. Brute force just isn't the answer. Because PowerColor had to follow AMD's guidelines, this implementation is already running at its limit. Sure, you could dial in higher fan speeds to cool things down, creating more noise in the process, but who really wants that? As we explained in AMD RX Vega 64: The Tom's Hardware Liquid Cooled Edition, even with higher frequencies and brutal power adjustments, it is almost impossible to get Radeon RX Vega running much faster. Instead, undervolting can achieve far better results.
First and foremost, the use of a suitable utility like OverdriveNTool works wonders. As always, though, your results will also depend on the quality of your GPU. We can't generalize; you'll have to compare your improvements to ours.
Temperatures & Frequencies
We’re using the GPU temperature value exclusively because that's what our test sample’s telemetry reports. Of course, the hot-spot temperature is a lot higher. Why? You can read all about in Does Undervolting Improve Radeon RX Vega 64's Efficiency? On PowerColor's Red Devil RX Vega 64, those readings are up to 14°C higher.
The following table shows a comparison of start and end values for temperatures and GPU (boost) frequencies. Just keep in mind that these clock rates can be considerably higher in games with significantly lower loads. For example, Wolfenstein 2's indoor environments might push the card to 1.63 GHz, only to knock it way down once you step outside.
| Initial Value | Final Value | |
|---|---|---|
| Open Test Bench | ||
| GPU Temperature | 32°C | 65°C |
| GPU Clock Rate | 1523 MHz | 1381 MHz |
| Ambient Temperature | 22°C | 22°C |
| Closed Case | ||
| GPU Temperature | 34°C | 64°C |
| GPU Clock Rate | 1523 MHz | 1375 MHz |
| Air Temperature in Case | 24°C | 47°C |
Temperature vs. Frequency
To better illustrate our findings, we plotted temperatures and frequencies during our sample's 15-minute warm-up phase. It's particularly interesting that there's such a small thermal difference between open and closed cases.
Frequencies in the gaming loop are about 100 MHz higher than what we measured from AMD's reference card. This average increase of 11% only improves gaming performance by 6-8%, which isn't particularly impressive.
The results of our stress test look similar:
IR Image Analysis Of The Board's Back
To round out this section, we take a look at board temperatures across several different load levels. To keep the test setup as practical as possible, we removed the backplate for IR measurements (since it doesn't help with cooling anyway). Comparative before/after tests show no difference in temperature or cooling performance.
Gaming
This card has no problem in our Witcher 3 gaming loop. Measurements of 68°C behind the GPU package and 66°C at the voltage converters are actually cool compared to some of the Radeon RX Vega cards we've tested. Does the situation change at all in a closed case?
Not really, no. In a closed case, we measure one degree higher at the voltage converters, while the area behind AMD's GPU rises two degrees. This is enabled by faster-spinning fans, since PowerColor sets a fairly aggressive temperature target. We'll be paying close attention to what that does to noise output.
Stress Test
The stress test reflects slightly lower power consumption than our gaming benchmark. However, certain components (like the voltage converters) still get a little warmer. This is ultimately the result of a more constant load, which can be difficult to keep up with.
Again, the temperatures only rise one to two degrees moving from an open bench table to a closed case. Of course, the fan speeds needed to make this possible increase as well.
In the end, PowerColor's cooler proves itself to be incredibly effective. All of our thermal readings land within a very comfortable range.
Heating Up & Cooling Down
The last two pictures show where the heating starts and where the circuit board is cooled most effectively.
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