AV1 3-way encoding barely used.

Hello,
I'm doing some tests using an RTX 5090 card, rendering 4K HDR videos using the nVidia NVENC encoder (DaVinci Resolve 20).

Source videos have the following specs:

Code: Select all

Format: HEVC
Format profile: Main 10@L5.1@High
Codec ID: hvc1
Bit rate: 84.6 Mb/s
Width: 3 840 pixels
Height: 2 160 pixels
Display aspect ratio: 16:9
Frame rate mode: Variable
Frame rate: 60.000 FPS
Color space: YUV
Chroma subsampling: 4:2:0
Bit depth: 10 bits
Color range: Limited
Color primaries: BT.2020
Transfer characteristics: PQ
Matrix coefficients: BT.2020 non-constant
Codec configuration box: hvcC


for encoding, I use the following nvenc settings:

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Quality: Restrict to 90000Kb/s
Encoding Profile: Main10
Keyframes: Automatic
Frame Reordering: Yes
Rate Control: Variable Bitrate
Split Mode: Split
Preset: Very Slow
Tuning: Ultra High Quality
Two Pass: Full
Lookahead: 16 frames
Disable Adaptive B-Frame
AQ Strenght: 8


The encoding process runs rendering almost 30/35 frames per second.
I've noticed the 3 encoders are barely used, though: they're never over 40/45% loaded.



Any reason / explanation? When I was using an RTX 4090 and DaVinci Resolve 19 I remember they were always used over 80% with the same settings.

I'm having the same issue. The 3 video encoders were all sitting around 21% during the entire time the render was going and the GPU utilization never passed 40% and was only pulling 190w.

I would like a solution to this as well because feels like I'm leaving a lot of performance on the table.

My render settings were: Format:

MP4 Codec: AV1 Type: Nvidia

3840x2160 60FPS

Quality restrict to 80,000 kb/s

Profile: Main
Key Frames: Auto

Frame reordering checked

Rate control QP
Split Mode: Split
Preset: Medium
Tuning: High Quality
Two Pass: Disable

Constant QP, 87, 112, 134

Lookahead 16 frames

Enable Adaptive b-frames checked

AQ Strength 8



PC specs:

GPU: RTX 5090 Gigabyte Aorus Xtreme Waterforce AIO
CPU: Intel Ultra 9 285k
Ram: 48GB (2x24) 8000MT/S CL40 CUDIMM
Motherboard: Asus z890 Apex

I'm having the same issue. The 3 video encoders were all sitting around 21% during the entire time the render was going and the GPU utilization never passed 40% and was only pulling 190w.

I would like a solution to this as well because feels like I'm leaving a lot of performance on the table.

My render settings were: Format:

MP4 Codec: AV1 Type: Nvidia

3840x2160 60FPS

Quality restrict to 80,000 kb/s

Profile: Main
Key Frames: Auto

Frame reordering checked

Rate control QP
Split Mode: Split
Preset: Medium
Tuning: High Quality
Two Pass: Disable

Constant QP, 87, 112, 134

Lookahead 16 frames

Enable Adaptive b-frames checked

AQ Strength 8



PC specs:

GPU: RTX 5090 Gigabyte Aorus Xtreme Waterforce AIO
CPU: Intel Ultra 9 285k
Ram: 48GB (2x24) 8000MT/S CL40 CUDIMM
Motherboard: Asus z890 Apex

I've done some additional tests, and for me, the issue is caused by the tuning parameter set to the new value, 'Ultra High Quality.'
If I lower it to an inferior setting, the encoders consistently operate at 85–90%.
It seems like this new tuning parameter has some issues. I understand that 'Ultra High Quality' is supposed to be slower, but not to the point of barely utilizing the hardware.

I've also tested the parameters you mentioned, and guess what? I can replicate your issue—low GPU utilization even with the 'Medium' preset. However, if I change the preset to 'Very Slow,' performance actually improves (70–75% GPU utilization).

These settings are a mess, if you ask me. There's something wrong with how the 'Tuning' and 'Preset' parameters interact with each other. Tweaking them leads to inconsistent results. Not exactly ideal when you own a €3,200 GPU, only to see it running at 40%.

By the way, I'm using NVIDIA drivers version 576.52.

I've also tested the parameters you mentioned, and guess what? I can replicate your issue—low GPU utilization even with the 'Medium' preset. However, if I change the preset to 'Very Slow,' performance actually improves (70–75% GPU utilization).

These settings are a mess, if you ask me. There's something wrong with how the 'Tuning' and 'Preset' parameters interact with each other. Tweaking them leads to inconsistent results. Not exactly ideal when you own a €3,200 GPU, only to see it running at 40%.

By the way, I'm using NVIDIA drivers version 576.52.

Very slow huh? I'll have to try that, thanks for the tip. It definitely seems like a mess, I don't know if it's a resolve issue, or just a driver issue. I'm also using 576.52 of the Studio Driver and the latest bios for my motherboard, so I have everything up to date.

Anyway, I try my rendering my next video in very slow and see how that goes and hopefully the next resolve update or NVIDIA driver improves things.