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When I inspect my GPU performance in the Task manager, Only 2 of my 4 GPUs are being used to GPU render (NOT Maxwell Fire interactive render, but Maxwell Render).
The 2 GPUs that are rendering are only using less than 15% of the GPU each.

1) Why is Maxwell nor using all of my GPUs to render?
2) Why is Maxwell Render using less than 15% of my GPUs?

System Specs:

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Operating System
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0101 - Operating System : Windows 11 Pro 64-bit (10.0, Build 22000) (22000.co_release.210604-1628)
0102 - Language : English (Regional Setting: English)
0103 - BIOS : FA
0104 - Processor : AMD Ryzen Threadripper 3970X 32-Core Processor (32 CPUs), ~3.7GHz
0105 - Memory : 262144MB RAM
0106 - Available OS Memory : 262018MB RAM

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Processor
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0201 - Caption : AMD Ryzen Threadripper 3970X 32-Core Processor x32 ~3700MHz
0202 - Current Clock Speed : 3700MHz

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Video Adapter
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CARD 01
0301 - Card Name : NVIDIA GeForce RTX 3090
0302 - Manufacturer : NVIDIA
0303 - Chiptype : NVIDIA GeForce RTX 3090
0306 - Display Memory : 4095 MB
0311 - Driver Version : 30.00.0015.1259

CARD 02
0301 - Card Name : NVIDIA GeForce RTX 3090 Ti
0302 - Manufacturer : NVIDIA
0303 - Chiptype : NVIDIA GeForce RTX 3090 Ti
0306 - Display Memory : 4095 MB
0311 - Driver Version : 30.00.0015.1259

CARD 03
0301 - Card Name : NVIDIA GeForce RTX 3090 Ti
0302 - Manufacturer : NVIDIA
0303 - Chiptype : NVIDIA GeForce RTX 3090 Ti
0306 - Display Memory : 4095 MB
0311 - Driver Version : 30.00.0015.1259

CARD 04
0301 - Card Name : NVIDIA GeForce RTX 3090 Ti
0302 - Manufacturer : NVIDIA
0303 - Chiptype : NVIDIA GeForce RTX 3090 Ti
0311 - Driver Version : 30.00.0015.1259

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04 - Memory | 256GB Ram
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0401 - Total Memory : 255.897 GB
0402 - Free Memory : 166.670 GB
0403 - Total Pagefile : 293.897 GB
0404 - Free Pagefile : 183.1006 GB

0405 - Bank Label : P0 CHANNEL A
0406 - Speed : 3600 MHz
0407 - Total Width : 64 Bits
0408 - Capacity : 32.00 GB

0405 - Bank Label : P0 CHANNEL A
0406 - Speed : 3600 MHz
0407 - Total Width : 64 Bits
0408 - Capacity : 32.00 GB

0405 - Bank Label : P0 CHANNEL B
0406 - Speed : 3600 MHz
0407 - Total Width : 64 Bits
0408 - Capacity : 32.00 GB

0405 - Bank Label : P0 CHANNEL B
0406 - Speed : 3600 MHz
0407 - Total Width : 64 Bits
0408 - Capacity : 32.00 GB

0405 - Bank Label : P0 CHANNEL C
0406 - Speed : 3600 MHz
0407 - Total Width : 64 Bits
0408 - Capacity : 32.00 GB

0405 - Bank Label : P0 CHANNEL C
0406 - Speed : 3600 MHz
0407 - Total Width : 64 Bits
0408 - Capacity : 32.00 GB

0405 - Bank Label : P0 CHANNEL D
0406 - Speed : 3600 MHz
0407 - Total Width : 64 Bits
0408 - Capacity : 32.00 GB

0405 - Bank Label : P0 CHANNEL D
0406 - Speed : 3600 MHz
0407 - Total Width : 64 Bits
0408 - Capacity : 32.00 GB

Sadly I’ve only 2x 3090 and I’m a bit jealous about your setup

In the task manager don’t check the GPU utilization, but switch to CUDA USAGE.

You will notice a 100% usage

Thank you for responding.

Unfortunately in Windows 11, the CUDA option in Task Manager does not exist.

When I view my GPU temperatures, I notice they are very low (30-45 degrees Celsius), so I figured if CUDA was being used the temperatures would increase.

Very frustrating, having great hardware, but not being able to fully utilize it.

Maybe send a response to Next Limit via your Portal and see what they say?

Larry, the gpu temps could not be a good indicator about your gpu usage.

My two 3090 are fully water cooled, ( with EKWB active backplate too) and even under full load they’re around 49/50

I would suggest to downgrade to windows 10 and stick with it for a while.

Another way would be deactivate 2 GPUs and see if using only 2 cards would change anything

I have contacted Maxwell support, and opened a Ticket.

1) GPU Temps:
- When GPU rendering in any other software (Maya, Blender, Davinci Fusion...) I at least see a fluctuation in GPU temps when rendering.
- While GPU rendering in Maxwell Render, (2) of my GPUs do Not change temps at all. (One of the reasons I don't believe they are being used).
- Matteo, I will take your suggestion, and disconnect the 2 GPUs I think are not being used to see if there is a difference in rendering.

2) Downgrade to Windows 10:
- Matteo, If downgrading to windows 10 is a definite fix, I will downgrade.
- Does Maxwell Render perform differently in Windows 10, than Windows 11?

Matteo, thank you for your suggestions I'm struggling here,
-Larry

Windows 11 its a new OS, and could have some compatibility issue with drivers/software not completely optimized.

Actually sticking to windows 10 could be a solution for the maximum balance between driver/hardware/software compatibility.

Maxwell render could handle easily 4 GPUs

At last we have in our studio an old workstation with 4x 1080ti paired with a 2990WX and work as intended.

I would try to render using only one gpu at time.

If I remember right, you can even start multiple rendering instances and select only one gpu for each render.

We will receive a workstation with 3x 3090ti in September so I can’t test any further for now.

If you downgrade to windows 10 make a full clean instal.

And use always the Nvidia Studio Driver.

Thank you Matteo.

-Larry