Driver fails, 470.86, Ubuntu 20.04

Headless 470.86 installs correctly into a Ubuntu 20.04 headless box.
I have a Nvidia T600 installed.
When I do a nvidia-smi command:

±----------------------------------------------------------------------------+
| NVIDIA-SMI 470.86 Driver Version: 470.86 CUDA Version: 11.4 |
|-------------------------------±---------------------±---------------------+
| GPU Name Persistence-M| Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util Compute M. |
| | | MIG M. |
|===============================+======================+======================|
| 0 NVIDIA T600 Off | 00000000:01:00.0 Off | N/A |
| 53% 51C P0 N/A / 41W | 0MiB / 3909MiB | 0% Default |
| | | N/A |
±------------------------------±---------------------±---------------------+

±----------------------------------------------------------------------------+
| Processes: |
| GPU GI CI PID Type Process name GPU Memory |
| ID ID Usage |
|=============================================================================|
| No running processes found |
±----------------------------------------------------------------------------+

When I try to run a video transcode on the system, the driver either crashes (nvidia-smi shows no gpu detected).
Or it gives up and faults back to the Intel i5.

Prepared to give whatever logs you need, I’ve been fooling around with this for over 2 weeks now. Have done 20 reinstalls of Ubuntu, while using every guide and tip to find while googling.

Please configure nvidia-persistenced to start on boot and make sure it keeps running. Then monitor temperatures using nvidia-smi.