That's what I thought.
I'm new to GPUs. I'm an electronic engineer, so I don't know the details of GPUs, Nvidia settings, parameters, etc., but I have a pragmatic considered approach.
What I have learned this evening is that reducing the power limit down makes things behave, and I can complete the test.
My current working theory is that there is either a power issue or a clock speed issue which the lower power limit prevents the GPU from entering. The GPU came from a friend, but maybe he dabbled with overclocking it in the past and didn't remember. Thanks all.