giofrida

PSA (bug?): core voltage spikes when recording with HEVC

Discussion created by giofrida on Jun 15, 2020
Latest reply on Aug 29, 2020 by giofrida

Hello.

Since I updated to the Adrenalin drivers I've been facing an annoying issue regarding the core voltage of my RX 480 card (specifically a XFX RX 480 8GB GTR edition). Using MSI Afterburner I lowered the core voltage (as well as configured a custom fan curve) to reduce the excessive heat and noise that came out from the card. These are my settings:

(maximum voltage is set to ideally 1.000V).

However, I noticed some voltage spikes when playing that push core voltage up to 1.200V, even higher than the stock one, that is 1.162V.

After many trial-and-error attempts to fix it I finally found the root cause of the problem, which is the H265 (HEVC) codec in the Radeon Relive settings. So in order to show this I made some tests using a game benchmark.

 

Test 1: Radeon Relive set to 'AVC'

As you can see the voltage is fixed to around 1.000V, as set in the Voltage/Frequency curve.

Test 2: Radeon Relive set to 'HEVC', without restarting MSI Afterburner

If I don't restart MSI Afterburner, the core voltage remains around 1.200V (at full load), without any spike, exceeding the stock voltage of 1.162V

Test 3: Radeon Relive set to 'HEVC'; MSI Afterburner restarted

Voltage spikes are clearly visible. It seems to me that Afterburner "tries" to set the core voltage but it gets overridden every ~4 seconds to around 1.200V from the Radeon software. These spikes increase the average core voltage, therefore reducing the effect of the undervolt.

 

Notes:

- I also tried uninstalling the Radeon software completely and installing the driver only. I get the same results when using OBS (as a replacement of Radeon Relive) with HEVC codec.

- I am pretty sure I didn't experience this issue with the "old" Crimson driver suite, but if needed I can check it out

 

Conclusions:

I don't know if this is a bug or is a totally expected behavior (maybe there are technical reasons to push up the voltage when recording with the H265 codec?) but I'm sure this could be very helpful for those who are experiencing the same problem, so I wanted to document it.

 

P.s: you can find the Afterburner logs attached in this post

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