Overclocking, Frequency, Temperature & Noise
Overclocking
The Radeon RX Vega 64 Nitro+ hits its limit much later than the reference design due to a superior thermal solution. It even approaches performance levels generally reserved for water-cooled models. There's really no reason to push the card any harder than we did; all you'd get would be more noise. When it comes to dialing in slightly higher clock rates (and performance) at the expense of big power consumption penalties, nothing has changed since we covered it at length in AMD RX Vega 64: The Tom's Hardware Liquid Cooled Edition.
Temperature & Clock Frequency
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 Sapphire's Radeon RX Vega 64 Nitro+, those readings were up to 13°C higher. But they never hit a level that could have caused problems.
Even using our maximum overclock, the HBM2's sensor loop reported temperatures under 80°C, which is also well within the acceptable range. Sapphire’s cooling solution keeps thermals right where they should be.
The following table contains the initial and final temperature with corresponding clock rate values:
| Initial Value | Final Value | |
|---|---|---|
| Open Test Bench | ||
| GPU Temperature | 39°C | 70°C |
| GPU Clock Rate | 1525 MHz | 1507 MHz |
| Ambient Temperature | 22°C | 22°C |
| Closed Case | ||
| GPU Temperature | 41°C | 70°C |
| GPU Clock Rate | 1529 MHz | 1507 MHz |
| Air Temperature in Case | 24°C | 43°C |
| Overclocking (Closed Test Bench, Witcher 3 4K) | ||
| GPU Temperature (~2944 RPM) | 29°C | 73°C |
| GPU Clock Rate | 1696 MHz | 1643 MHz |
| Air Temperature in Case | 24°C | 50°C |
Temperature vs. Clock Frequency
To better illustrate our findings, we plotted temperatures and frequencies during our sample's 15-minute warm-up phase:
IR Image Analysis For The Board's Back
To round out this section, we take a look at board temperatures across several different load levels.
Gaming & Overclocking
The thermal image shows us that all areas of the board stay fairly cool thanks to adequate airflow. The Radeon RX Vega 64 Nitro+ is set to hold a maximum GPU temperature of 70°C no matter what, which benefits the area under the package. The voltage converters fall well within an acceptable range, and the phase doublers receive additional cooling from the backplate.
The same observations apply to our closed case scenario, with board temperatures only increasing by ~3°C.
If we use our maximum overclock and adjust the fan speed, we still end up with enough airflow to keep the GPU at ~73°C in a closed case. That's despite a power consumption reading of almost 390W.
The area right underneath the package remains below 80°C, even though there is some measurable heat transfer from the direction of the voltage converters. In light of this, the decision to keep the MLCC this way makes sense. The voltage converters and their hefty 77°C don’t pose a risk.
Stress Test
Compared to our gaming workload, the stress test heats up the card a bit more. However, the difference is marginal.
In a closed case, the board temperature rises by up to 2°C at the critical points, and that's all. We're impressed by this result.
Warm-Up & Cool-Down
Lastly, we look at warm-up and cool-down. The pictures illustrate nicely where most of the heat comes from, and where the cooling solution focuses its efforts.
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